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Molecular materials - towards quantum properties (MOLMAT-Q)

Molecular Materials attract growing interest in science and technology due to its (i) cutting-edge basic research projects targeting physics within the quantum regime (e.g. molecular spintronics, nuclear spin manipulation) and (ii) applied research leading to new applications and devices close to market introduction (e.g. optoelectronics). This session takes place as part of the series of conferences “Molecular Materials” (MOLMAT).

Scope:

Molecular Systems whose structures and components, due to their inherent nanoscale size, exhibit unusual or enhanced properties partially uniquely expressed in the quantum regime. The processing and manipulation of the quantum properties of molecular materials as well as the fabrication of devices with new sustainable approaches are crucial issues towards a technology based on intelligent materials in Europe. Molecular Materials are foreseen to have a pervasive impact on industry, economy and many aspects of society, including our everyday life.

This symposium is aimed at providing a forum where the quickly growing community of scientists and researchers working on functional molecular nanosystems based on magnetic and photophysical materials, and more in general, how Molecular Materials achieve an impact in nanoscience and nanotechnology.

A particular emphasis is given to the bottom-up approach since the ability to manipulate the local nanoscopic environment is crucial to access fundamentally new classes of physical effects in the nanoregime showing unprecedented properties and performance. In fact, despite the progress of the last ten years in the area of molecular spintronics and photophysics much remains to be done to achieve coherent control at the nanoscale.

This symposium will bring together experts in the fields of fundamental physics, synthetic chemistry, material science, as well as device engineering.

Obtaining such cross-over knowledge is also crucial from an applicative point of view, and therefore for society. This is first of all a consequence of the connection between the development of organic electronics and molecular spintronics, which are about to be applied in first consumer electronics devices. In the longer term, it can be reasonably envisioned that ongoing research may address quantum logics and computation based of the inherent quantum character of molecules.

Hot topics to be covered by the symposium:

  • Surface-confined synthesis of Novel Materials
  • Molecular Magnetic Materials • Spintronic Materials
  • 2D Graphenoids
  • Light Emitting Devices (LEDs, LETs, LECs)
  • Fundamental issues on organic materials properties at the nanoscale
  • Design and synthesis of dynamic supramolecular nanostructured materials
  • p- conjugated (macro)molecules
  • Electroactive and photoactive supramolecular architectures
  • Self-assembly and self-organization
  • Hybrid nanostructured multifunctional architectures
  • Molecular mechanics and dynamic simulation of supramolecular arrangements
  • Molecular Quantum Materials
  • Nanofabrication
  • Bottom-up nanopatterning
  • Nanoscale tools and nanomanipulation
  • Scanning Probe Microscopies
  • Nanooptics and fast spectroscopy of functional materials
  • Optical properties of organic interfaces
  • Local properties of spatially confined nano-objects
  • Charge injection and transport in hybrid metal - supramolecular architectures
  • Organic solar cells
  • Nanoelectronics: Organic Thin Film Transistors and supramolecular nanowires
  • Supramolecular switches and motors
  • Quantum Information Processing and Quantum Computation

List of invited speakers:

  • Albert Fert (Thales-Lab Paris, France, Nobel Laureate in Physics 2007)
  • Karl Leo (IAPP Dresden, Germany)
  • Paul Blom (Max-Planck-Institute for Polymers, Mainz, Germany)
  • Marco Affronte (Modena University, Italy)
  • Herre van der Zant (TU Delft, The Netherlands)
  • Richard Winpenny (Manchester University, UK)
  • Luis Hueso (NanoGUNE, San Sebastian, Spain)
  • Wolfgang Wernsdorfer (Institute Néel, Grenoble, France)
  • Eugenio Coronado (Valencia University, Spain)
  • Franc Meyer (Göttingen University, Germany)
  • Roberta Sessoli (Florence University, Italy)

International Advisory Board:

  • Jean-Pierre Sauvage (Strasbourg)
  • Bernard Barbara (Grenoble)
  • Günther Reiter (Freiburg)
  • Jose-Ramon Galan-Mascaros (Taragona)
  • Marcel Mayor (Basel)
  • André-Jean Attias (Paris)

Publication:

Papers will be published in Beilstein Journal of Nanotechnology.

Symposium organizers:

Mario Ruben
Karlsruhe Institute of Technology
INT-KIT, PF 3640
D-76021 Karlsruhe
Germany
Tel: +49 (0)724 7826781
mario.ruben@kit.edu
www.ruben-group.de
or
IPCMS- CNRS-UMR 7504
Université de Strasbourg
23, Rue du Loess, BP.43
F-67034 Strasbourg cedex 2
France

Azzedine Bousseksou
CNRS, Laboratoire de Chimie de Coordination, UPR8241
205, route de Narbonne
F-31077 Toulouse cedex 04
France
Phone: +33 (0)5 61 33 31 69
Fax: +33 (0)5 61 55 30 03
boussek@lcc-toulouse.fr

Guillem Aromi
Universitat de Barcelona
Departament de Química Inorgànica
Diagonal, 645
08028 Barcelona
Spain
Phone: +34 93 403 9760
guillem.aromi@qi.ub.es

Start atSubject View AllNum.Add
09:00 Introduction and opening remarks (Mario Ruben)    
 
Quantum properties of integrated Carbon based nanomaterials : Mario Ruben
09:15
Authors : M. Affronte, A. Candini, V. Corradini, V. Bellini.
Affiliations : CNR Institut Nano S3 Modena and University of Modena

Resume : Hybrids made of carbon based nanomaterials and molecular nanomagnets (MNM) represent a viable route for quantum spintronics: magnetic molecules can be used as elementary units with well defined quantum features while graphene and CNT are excellent templates to make electronic devices and interconnects at the nano-scale. Prototypical hybrids mimicking spintronics devices have been recently realized [1]. Yet, in order to fully exploit their novel quantum features we need to control the interplay between MNM and graphene. Here I?ll focus on the interaction between mononuclear (bis-)phtalocianine and graphene. More specifically, I?ll discuss the case of FePc and LnPc_2 (Ln=Tb, Dy, Er) on graphene grown on Ni(111) surface by presenting our recent low temperature XAS and XMCD investigations. When molecules are deposited directly on Ni(111) surface we observe an exchange coupling of the magnetic centre with the Ni substrate. We firstly evaluate the interplay between this exchange and the single atom anisotropy in different cases including the cases of paramagnetic Fe, axial anisotropy (Tb) and in-plane anisotropy (Er). This exchange coupling is weakened by the insertion of graphene between the molecules and the Ni(111) surface. These results are interpreted by DFT calculations that account for different configurations of local bonds. [1]Graphene Spintronic Devices with Molecular Nanomagnets. A. Candini, S. Klyatskaya, M. Ruben, W. Wernsdorfer and M. Affronte Nanoletters 11, 2634?2639 (2011)

M.M.I..1
09:45
Authors : M. Cittadini 1, M. Bersani 1, F. Perrozzi 2, L. Ottaviano 2 3, W. Wlodarski 4, A. Martucci 1
Affiliations : 1 Industrial Engineering Department, University of Padova, Padova, 35131, Italy; 2 Dipartimento di Scienze Fisiche e Chimiche, Universita` dell’Aquila Via Vetoio 10, 67100 L’Aquila, Italy; 3 CNR-SPIN Uos L’Aquila, Via Vetoio 10, 67100 L’Aquila, Italy; 4 School of Electrical and Computer Engineering, RMIT University, Melbourne, Australia.

Resume : Graphene oxide (GO) consists in atomically-thin graphene sheets, covalently decorated with O-containing functional groups, so it contains a mixture of sp2- and sp3-hybridized C atoms. The as-synthesized GO is insulating but, with a controlled de-oxidation, partially reduced, pr-GO acts as a semiconductor. Moreover, its highly 2D nature, makes it promising for photocatalysis. In this work GO is used as optical gas sensor, prepared depositing pr-GO flakes over a monolayer of gold nanoparticles (NPs), chemically attached to a functionalized fused silica substrate. The coupling between flakes and NPs has the aim of combining the semiconducting and photocatalytic behavior of the pr-GO with the Localized Surface Plasmon Resonance (LSPR) of Au NPs. Their synergistic interplay resulted in an enhancement of the photocatalytic properties of GO, extending it to the visible range where the LSPR of Au NPs can be used as optical probe. The LSPR is extremely sensitive to the changes in the dielectric properties of the surrounding medium. Here we expect an even larger enhancement of this effect induced by the electronic coupling of Au NPs and GO and the interactions of GO with reducing (H2) and oxidizing (NO2) gases. While the use of GO for gas sensing has been covered in many reports, with the GO–Au NPs system already employed as a resistive gas sensor, this is the first time that GO is used as sensing material in an optical sensor with good and reversible responses and fast kinetics.

M.M.I..2
10:00
Authors : P. Du, D. Kreher, F. Mathevet, F. Charra, T. Pick, B. Helms, A.-J. Attias
Affiliations : Université Pierre et Marie Curie, Paris, France; CEA Saclay, France; LBNL, Berkeley, USA

Resume : One of the critical challenges in the field of two-dimensional (2D) supramolecular self-assemblies at surfaces is: how to exploit the room above the substrate, to provide to the physisorbed adlayer potential functionalities in view in view of solving scientific problems and applications in nanoscience? This is why we developed the Janus tecton concept. This is a versatile molecular platform based on the design of three-dimensional (3D) building blocks consisting of two faces linked by a pillar: one face is designed to steer 2D self-assembly on sp2 carbon flat surfaces, the other one exposes the desired functionality (either a chemical or functional unit) above the substrate. Scanning tunneling microscopy and molecular mechanics calculations show effectively that we offer a generic platform exposing a functionality in the third dimension with a well-controlled lateral order, paving the way for the noncovalent functionalization of sp2-carbon materials, opening interesting perspectives for applications in nanoscience as we will demonstrate in this presentation. Moreover, the successful self-assembly on graphene, together with the possibility to transfer the graphene monolayer onto various substrates, considerably expends the domains of application of our functionalization strategy,

M.M.I..3
10:15
Authors : Danny E. P. Vanpoucke, Toon Verstraelen, Mathias Vandichel, An Ghysels, Kurt Lejaeghere, Veronique Van Speybroek
Affiliations : Center for Molecular Modeling, Ghent University, Technologiepark 903, Zwijnaarde 9053, Belgium

Resume : Metal-organic frameworks (MOFs), also referred to as hybrid organic-inorganic materials, have emerged as a class of highly tunable crystalline materials showing ultrahigh porosity and internal surface areas. These materials consist of two secondary building units (SBUs): (1)metal(-oxide) nodes are connected through (2)organic ligand molecules. The variability of the SBUs allows an almost limitless set of possible combinations, each having its own specific properties. In addition, functional groups can be added to the linkers giving rise to modified host-guest interactions. The resulting MOFs are of great interest for many important industrial applications such as clean energy, hydrogen storage and carbon-dioxide capture. Also catalysis, gas-separation and sensor applications are fields of interest. In this work, we present an ab-initio study of functionalized MIL-47(V) MOFs. We show how different linkers influence the stability of the MOF and its adsorption of CO2. Using the Hirshfeld-I scheme charge transfer between the SBUs and the functional groups is discussed. Finally, a protocol is given for calculating high quality mechanical properties (e.g. bulk moduli) and vibrational spectra, providing thermal contributions to the energy. [1]Biswas S., Vanpoucke D.E.P., et al., J. Phys. Chem. C 117,22784-22796(2013) [2]Vanpoucke D.E.P., Bultinck P.,and Van Driessche I.,J. Comput. Chem. 34,405-417(2013) [3] Ghysels A.,Vanpoucke D.E.P.,Lejaeghere K.,et al., in preparation

M.M.I..4
10:30 Morning Break    
 
Opto-electronic molecular materials : Nuria Crivillers
11:00
Authors : R. Brueckner, M. Sudzius, A.A. Zakhidov, A. Mischok, V. Lyssenko, R. Scholz, H. Froeb, and K. Leo*
Affiliations : Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany *:also: King Abdulllah University of Science and Technology, Saudi Arabia

Resume : Organic microcavities offer fascinating opportunities to study the interactions of light and organic matter. These observations are made possible by the large oscillator strengths and exciton binding energies provided by organic semiconductors. For electrically driven devices, highly conductive electrodes have to be integrated. For this purpose metallic electrodes are under study, but the large absorption properties of metals are generally to prevent optical coherence. In this talk, we will focus on the impact of metallic structures implemented into organic microcavities. Optimizing the structural design and introducing a higher order confinement are beneficial to maintain optical coherence at low thresholds. First, a homogeneous silver layer of 40nm thickness is implemented into a high quality organic microcavity. By exciting this structure non-resonantly the transition from a single photonic cavity mode to two coupled Tamm states is observed Optimizing the design reduces the overall optical losses and increases the Q factor to 650 allowing for the observation of coherent emission from cavity photons and Tamm plasmons at room temperature. Furthermore, lateral confinement of the optical modes can be introduced by generating an optical gain grating or by structuring the metal layer by means of photo-lithography. Structuring the metal layer into periodically placed stripes leads to the observation of surface plasmon polaritons and Bloch-like photonic bands. Above the lasing threshold, macroscopic coherence on different Bloch states is observed.

M.M.II..1
11:30
Authors : Umberto Giovanella(1), Giuseppe Leone(1), Francesco Galeotti(1), Fabio Bertini(1), Sajjad Hoseinkhani(1), William Porzio(1), Giovanni Ricci(1), Wojciech Mróz(1), Francesco Meinardi(2), Chiara Botta(1)
Affiliations : (1) CNR, Istituto per lo Studio delle Macromolecole (ISMAC), via E. Bassini 15, 20133 Milano, Italy (2) Dipartimento di Scienze dei Materiali, Università di Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy

Resume : A facile and robust approach for fabricating structured, blue-emitting polymer hybrids is explored by grafting poly(styrene) incorporating π-conjugated terfluorene side-chains, to fluoromica silicate layers through surface-initiated nitroxide-mediated polymerization [1]. The hybrids exhibit blue photoluminescence quantum yield as high as 0.90 in the solid, and significantly enhanced thermal and chemical stabilities with respect to the organic precursors. The successful assessment of the hybrid material as efficient emitter in a light-emitting device is accomplished, and we shed light onto the not straightforward mechanism responsible for its emission. The layered hybrid approach allows us to achieve, at the same time, planarization and chemical and photo- stability of short oligo(fluorene)s whose emissive properties are enhanced thanks to exciton localization. Lying-flat intercalated terfluorene moieties are sensitized by non planar conformers grafted onto the outer polymer chains, that envelop the silicates, through a resonant energy transfer mechanism. Single layer solution processable device displays deep blue electroluminescence with an external quantum efficiency of 1.2 %, maximum luminance close to 1000 cd/m2, chromaticity coordinates of (0.16;0.11) and low efficiency roll-off thanks to the separation of the emissive region from the charge transport one. [1] Leone et al. J. Mater. Chem. C, 2013, 1, 6585

M.M.II..2
11:45
Authors : Cheong Shin, Won-Kook Choi and Jeon-Kook Lee
Affiliations : Interface Control Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea

Resume : Quantum dots (QDs) are uniquely suited for use as lumophores in light emitting devices for large-area planar lighting. We use the inorganic semiconductors as a charge transport layers and demonstrate devices with light emission. The low luminescence was attributed to luminescence quenching of the QDs in conductive electrodes, QD charging, and the imbalance in the polarity of charges injected into the device. Mechanically smooth films were chosen to prevent electrical shorts between the semiconductor and the QDs. We grow semiconducting oxide films with low free-carrier concentrations to minimize the quenching of the QD EL. The hole transport layer (HTL) and the electron transport layer (ETL) having similar carrier concentrations and energy-band offsets to the QDs were used because the electron and the hole injection into the QD layer should be balanced. Metal oxides offer a deposition-dependent morphologies and conductivities. For the ETL and the HTL, we selected a 40-nm-thck ZnO:SnO2(ZTO) and InGaZnOx(IGZO) with a resistivity of 10 cm. To improve the emission intensities, we observed the effects of the spin coating parameters and the concentrations of QD colloidal solutions. As the spin coating speeds were decreased from 2,000 to 500 rounds per minute (rpm), QD layer uniformities were improved. To reduce the morphologically induced electrical shorts in the device, we control the deposition parameters of ZTO or IGZO sputtering. We deposit transport layer onto the ZnSe:ZnS QDs layers formed on the transport layers. We use the Indium Tin Oxide (ITO) electrode on the glass substrate. Adhesion between the QDs layers and the ZTO layer was improved by using the molecular linker, 2-carboylehtylphosphonic acid (CAPO).We demonstrate the role of the QDs concentration on the luminescence properties. Our devices were measured without environmental packaging and in atmospheric conditions. We obtain the bright and uniform pixel at 10V applied bias. Light emitting uniformity was improved by reducing the rpm of QD spin coating. In the case of QD concentration of 15 mg/mL, we observe the bright electroluminescence at 12V applied bias. Much of the decrease in QD luminescence can be attributed to additional quenching by the free carriers in the ETL.

M.M.II..3
12:00
Authors : E. Coronado, J. P. Prieto-Ruiz, H. Prima
Affiliations : Instituto de Ciencia Molecular (ICMol). Universidad de Valencia (Spain)

Resume : Spin-based electronics is one of the emerging branches in today?s nanotechnology and the most active area within nanomagnetism. So far spintronics has been based on conventional materials like inorganic metals and semiconductors. Still, an appealing possibility is that of using molecule-based materials, as components of new spintronic systems [1]. In particular, by taking advantage of a hybrid approach one can integrate molecular materials showing multifunctional properties into spintronic devices. In this talk we illustrate the use of this approach to fabricate multifunctional molecular devices combining light and spin-valve properties (i.e., Spin-OLEDs). So far only one report has been published which is based on the fabrication of an organic light emitting diode (OLED) with ferromagnetic electrodes [2]. Our approach is based on the use of a HyLED (Hybrid Light Emitting Diode) structure in which Fe or LSMO and Co are used as ferromagnetic electrode. This device works simultaneously as a spin valve and an electroluminescent device at low temperatures [3]. This new approach leads to a robust organic luminescent device in which light emission can be enhanced and modulated upon application of an external magnetic field. [1] J. Camarero, E. Coronado, J. Mater. Chem. 2009, 19, 1678. [2] T. Nguyen, E. Ehrenfreud, Z. Valy Vardeny, Science 2012, 337, 204. [3] ?Opto-spintronic device and its fabrication method?.E. Coronado Miralles; H. Prima Garc?a, J.P. Prieto Ruiz. Spanish National Patent. Ref. 201300083, 2013, Spanish Office of Patents and Trademarks. Ministry of Industry, Energy and Tourism.

M.M.II..4
12:30 Lunch Break    
 
Molecular Functions : Jose Sanchez Costa
14:00
Authors : R. Sessoli,a M.-E. Boulona, M. Manninia, L. Pogginia, A. Caneschia, A. Rogalev b, F. Wilhelm b, A. Vindigni,a M. Scarrozza,d P. Barone,d S. Picozzi,d
Affiliations : a Dip.to di Chimica ‘Ugo Schiff’, Università degli Studi di Firenze & INSTM RU, 50019 Sesto Fiorentino, Italy. b European Synchrotron Radiation Facility, 38000 Grenoble, France c Laboratorium für Festkörperphysik, ETH Zürich, CH-8093 Zürich, Switzerland d Consiglio Nazionale delle Ricerche CNR-SPIN, 67100 L’Aquila, Italy

Resume : Chiral magnetic structures have been recently the focus of intense research because they offer the possibility to store information in topological protected structures like skyrmions. Chirality and magnetism are also directly connected in the interaction between matter and electromagnetic radiation through the magneto-chiral dichroism and birefringence. Magneto-chiral dischroism (MCD), a non-reciprocal effect with different absorption of unpolarized light by systems with opposite chirality in the presence of a magnetic field, is a fascinating phenomenon that has been suggested to be at the origin of homochirality of life on the earth and observed only recently. It is in general very weak, being assumed in first approximation to be related to the product of natural (NCD) and magnetic circular (MCD) dichroism, and only few examples are available in literature with limited information on the factors that originate the phenomenon. We report here a detailed synchrotron investigation of the magneto-chiral effect detected at the 3d-metal K edge in two isostructural molecular helices comprising either isotropic Manganese(II) or anisotropic Cobalt(II) bridged by stable organic radicals. The experiments have revealed a strong magneto-chiral dichroism associated with the non-collinear spin structure of the CoII derivative, which is also the archetype of Single-Chain Magnets, i.e. one-dimensional structures showing magnetic bistability due to short-range magnetic correlation. Interestingly, the chiral nature of these molecular helices allows the presence of novel magneto-electric effects. Density Functional Theory calculations have in fact revealed that the electric polarization of the molecular helix is affected by the relative alignment of neighbouring metal and radical spins, opening the perspective of controlling the magnetization dynamics of these one-dimensional structures through the application of an electric field. The authors acknowledge the financial support of the European Research Council through the AdG MolNanoMaS and of Italian MIUR through FIRB project n° RBAP117RWN.

M.M.III..1
14:30
Authors : Marco Caputo, Giovanni Di Santo, Mirko Panighel, Vajiheh Alijani Zamani, Luca Petaccia, Claudia Struzzi, Marcello Coreno, Monica De Simone, Guido Fratesi, Andrea Goldoni
Affiliations : Elettra - Sincrotrone Trieste, s.s. 14 km 164.5 in Area Science Park, 34149 Trieste, Italy; INSTM - Elettra, Lab. Micro & Nano-Carbon, s.s. 14 km 164.5 in Area Science Park, 34149 Trieste, Italy; Department of Physics, Trieste University, Via Valerio 2, 34127 Trieste, Italy; CNR-IMIP, Area della Ricerca di Roma 1, Monterotondo Scalo, Italy; ETSF, CNISM, and Dipartimento di Scienza dei Materiali, Milano-Bicocca Univeristy, via Cozzi 55, 20125 Milano, Italy

Resume : The recent discovery of superconductivity in polycyclic aromatic compounds such as alkali metal doped picene, dibenzopentacene etc. revitalized the study of superconductivity in organic compounds, first of all alkali metal doped C60. Alkali metal doped C60 systems share with the high Tc cuprates superconductors the strong electron-electron correlation that drives the Mott metal-to-insulator transition in proximity of the optimum doping condition. Unfortunately, unlike the cuprates case, alkali metal doped C60 undergoes to phase separation for certain doping values, and this prevents a continuous tuning of doping in order to maximize its Tc. Here we present a novel approach based on a C60-Picene heterojunction that allows the tuning of C60 charge state by alkali metal doping without falling in the phase separation. Ultraviolet and X-ray photoemission spectroscopy data on seven C60-Picene heterojunctions thick film indicate always a metallic phase despite the doping level and that the doping electrons belong only to C60.

M.M.III..2
14:45
Authors : Anne Bleuzen, Virgile Trannoy, Giulia Fornasieri, Sophie Lepoutre, David Grosso, Marco Faustini
Affiliations : A. Bleuzen, V. Trannoy, G. Fornasieri, ICMMO-UMR 8182, Equipe de Chimie Inorganique, Université Paris-Sud, 91405 Orsay Cedex (France) ; S. Lepoutre, D. Grosso, M. Faustini, LCMC Paris, Université Pierre et Marie Curie-Paris 6 and CNRS, Collège de France, 11 place Berthelot 75231 Paris (France)

Resume : Compounds exhibiting bistability in their physical properties as a function of external stimuli offer appealing perspectives for high-density information storage provided that i) a processing step allows the integration of the functional object into real applications and ii) the bistability in the physical properties is retained in the processed nanomaterial. The chemistry of Prussian blue analogs (PBA) was chosen to elaborate the bistable nano-objects either for the intrinsic molecular bistablity exhibited by some PBAs or as an appealing source of oxides and alloys designed to exhibit finely tuned magnetic properties. In order to assemble and organize the functional objects, solids exhibiting well-defined pore size, pore shape and pore organization, which can besides be deposited onto various substrates are particularly suited. Nano-structured oxides elaborated via sol-gel chemistry combined with surfactant micelle templating gather all these capabilities.[1] Here we show how the guided placement of the bistable nano-objects onto a substrate has been possible thanks to an appropriate series of chemical processes.[2] [1] A. Fisher, M. Kuemmel, M. Linden, C. Boissière, L. Nicole, C. Sanchez, D. Grosso, Small, 2006, 2, 4, 569-574. [2] S. Lepoutre, D. Grosso, C. Sanchez, G. Fornasieri, E. Rivière, A. Bleuzen, Adv. Mater., 22, 3992–3996, 2010.

M.M.III..3
15:00
Authors : Oleg V. Kolosov, Peter D. Tovee, Manuel Pumarol, Nicholas D. Kay, Benjamin J. Robinson
Affiliations : Physics Department, Lancaster University, Lancaster, LA1 4YB, UK www.nano-science.com

Resume : Two-dimensional (2D) materials such as graphene, MoS2, Bi2Se3 possess outstanding electrical, thermal, and mechanical properties. While electronic or optical properties are the main focus of research, their nanoscale mechanical and thermal properties of these materials are extremely important for the fundamental understanding and applications of these 2D nanostructures. We use a combination of scanning probe microscopies that combines low frequency and ultrasonic vibrations to map a wide dynamic range of stiffnesses from 0.02 to 2000 N/m with the lateral resolution of few nanometres. That allowed us to investigate results of residual stresses in supported graphene layers that revealed themselves as broken mechanical contact at the interface between graphene layer and the substrate, as well as to explore nanomechanical behaviour of few layer suspended graphene, MoS2 and Bi2Se3 films. We directly observed the transition of graphene layer deformation from plate to stretched membrane behaviour, and created nanoscale maps of shell instability for few layer graphene sheets, providing insight to the stresses in the free standing graphene films. We also addressed the challenge of exploration of thermal phenomena in graphene nanostructures by scanning thermal microscopy in high vacuum environment that allowed us to directly map thermal transport in suspended and suppored graphene layers with nanoscale resolution, and to explore both ballistic and diffusive regimes of heat transfer.

M.M.III..4
15:15
Authors : Judith Niedenführ, Bastian Feldscher, Jan-Philipp Broschinski,Thorsten Glaser, Andrei Postnikov, and Daniel Wegner
Affiliations : Pysikalisches Institut, Westfälische Wilhelms-Universität, Münster, Germany ; Fakultät für Chemie, Universität Bielefeld, Bielefeld, Germany ; Laboratoire de Chimie et Physique, Université de Lorraine, Metz, France

Resume : A key to building functional devices on the basis of single molecule magnets (SMMs), be it for potential high-density memory storage or molecular-electronics applications, is the ability to deposit and manipulate these large organic molecules on surfaces in a controllable and reproducible way. We have succesfully applied two different unconventional preparation techniques, namely pulse injection and rapid heating, for in-situ deposition of the Cu3-triplesalen complex onto a Au(111) surface. These complexes are the building blocks for a new generation of promising SMMs, which combine a high-spin ground state with a large magnetic anisotropy. The comparison of both techniques allows us to evaluate their advantages and drawbacks. The Cu3-triplesalen molecules have been studied using a combination of scanning tunneling microscopy (STM) and spectroscopy (STS). We discuss details of the electronic structure and its consequences on the internal spin coupling and compare these with first-principle calculations within the framework of the density-functional theory adddressing notably the charge density resolved into „slices“ at different energy windows. The comparison is also done for the slightly modified Cu3-triplesalalen complex which is designed to exhibit an enhanced ferromagnetic coupling.

M.M.III..5
15:30
Authors : E. Bellido,a P. González-Monje,a,b M. Guardingo, a,b F. Novio a,b and D. Ruiz-Molina a,b*
Affiliations : a Consejo Superior de Investigaciones Cientificas, ICN2 Building , Campus UAB ,08193 Bellaterra (Barcelona), Spain; b Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain

Resume : The controlled engineering of coordination structures on surfaces is a challenging area of growing interest and technological relevance in chemistry and materials science. We describe here the use of AFM tips to dispense less than femtoliter droplets of precursor solutions containing both the organic bridging ligands and metal ions building blocks on a target area of a surface. Thus each droplet can act as a reactor vessel to confine the coordination polymerization reaction while controlling the incubation conditions to yield the desired structure (SMMs, MOFs, Spin-Crossover, etc…). Moreover, due to its nanoscale positioning and imaging abilities, this technique is uniquely able to dispense localized nanostructures with control over the absolute placement at fixed device coordinates. For instance, it enabled us to structure SMMs on the most sensitive areas of a micro-SQUID sensor and to measure the dynamic magnetization of a few molecular layers. All this process is done without the need of any previous functionalization of neither the molecule nor the substrate, while controlling the number of molecular units deposited on each array. These results open new avenues for all the possible applications that can be derived from the implications of functional molecular materials on devices for future and emerging technologies. References: Nanoscale, 2013,5, 12565-12573; Sci. Rep. 2013 3 : 1708 | DOI: 10.1038/srep01708; Chem. Soc. Rev., 2012,41, 258-302; Langmuir 2012, 28, 12400; Small 2012, 8, 1465; Chem. Commun., 2011, 47, 5175. App. Phys. Lett. 2011, 99, 032504; Adv. Mater. 2010, 22, 352.

M.M.III..6
15:45
Authors : Michele Serri, Wei Wu, Luke R. Fleet, Nicholas M. Harrison, Cyrus F. Hirjibehedin, Christopher W. M. Kay, Andrew J. Fisher, Gabriel Aeppli, Sandrine Heutz
Affiliations : London Centre for Nanotechnology, Imperial College London and University College London

Resume : Phthalocyanines (Pcs) are polyaromatic molecules that are easily processed as thin films and nanostructures and are routinely used as semiconductors in optoelectronic applications such as solar cells. They are also able to accommodate a transition metal which may bear an unpaired spin, and may therefore display magnetic order in both thin film and single crystal phases. However, the transition temperatures have traditionally been very low, limiting practical applications. Here it is shown that CoPc can be prepared as an anti-ferromagnet with a magnetic exchange energy up to 100K, well above the boiling point of liquid nitrogen, and one order of magnitude higher than other Pc analogues. This behaviour is observed in flexible thin films and in nano-powders, but can be suppressed in the single crystal, leading to the possibility of magnetic switching. The unusually high and structure-dependent magnetic coupling is rationalised by high spin density on the dz2 orbital, and room temperature magnetism in co-facial structures has been predicted. The strongly one-dimensional nature of the magnetic chain and the S=1/2 quantum number of the cobalt, coupled with the semiconducting properties of the thin films make this system particularly interesting for quantum information processing and spintronics. M. Serri et al., Nature Commun. 5 (2014) 3079

M.M.III..7
16:00
Authors : Franc Meyer, Benjamin Schneider, Markus Steinert, Serhiy Demeshko, Sebastian Dechert
Affiliations : Institute of Inorganic Chemistry, Georg-August-University, Tammannstr. 4, D-37077 Göttingen.

Resume : Our group has developed a wide variety of pyrazolate-derived binucleating ligand scaffolds for preorganizing two (or more) metal ions in close proximity.[1] Such systems allow for tuning and controlling cooperative electronic and magnetic properties in elastically coupled oligometallic systems. A particular pyrazolate-based rigid ligand provides two terpyridine-like {N3} binding pockets and forms rugged [2´2] grid complexes with a variety of metal ions.[2] This presentation will focus on Fe4 grids that show sequential spin-crossover (SCO) and redox transitions, and that can be deposited on surfaces.[3] Configurations such as A1 and A2 have been obtained by proper ligand design and represent attractive molecular building units for quantum cellular automata (QCA).[4] Novel defect-grids B have a "structurally soft" H-bonded vertex and can serve as magnetic sensors.[5] Acknowledgment: Financial support by the DFG (SFB 1073) is gratefully acknowledged. References 1. J. Klingele, S. Dechert, F. Meyer, Coord. Chem. Rev. 2009, 253, 2698-2741. 2. J.I. van der Vlugt, S. Demeshko, S. Dechert, F. Meyer, Inorg. Chem. 2008, 47, 1576-1585. 3. B. Schneider, S. Demeshko, S. Dechert, F. Meyer, Angew. Chem. Int. Ed. 2010, 49, 9274-9277. 4. B. Schneider, S. Demeshko, S. Neudeck, S. Dechert, F. Meyer, Inorg. Chem. 2013, 52, 13230-13237. 5. M. Steinert, B. Schneider, S. Dechert, S. Demeshko, F. Meyer, submitted

M.M.III..8
 
Poster Session : Mario Ruben
16:30
Authors : Takashi Uchihashi
Affiliations : National Institute for Materials Science

Resume : Semiconductor surfaces covered with monolayer metal atoms constitute a family of highly-ordered low dimensional materials. Recently, we have demonstrated that monatomic indium layer on silicon surface (In/Si(111)) becomes superconducting around 3 K by performing direct electron transport measurements [1]. Since the indium layer is atomically thin, its superconducting properties will be strongly affected and tuned by growing magnetic molecular layer on top of it. One of the exciting goals is to create a 2D topological superconductor and Majorana fermions by introducing the Rashba effect and the exchange interaction between superconducting and magnetic layers [2]. In this talk, we report our first efforts to realize molecule-surface superconductor hybrid systems. Cu/Co-Phthalocyanine molecules were found to be self-assembled on the In/Si(111) surface with specific periodic structures, suggesting molecule-dependent interactions with the substrate. Superconducting transition was clearly observed for this hybrid structures by electron transport measurement. Scanning tunneling spectroscopy measurements revealed locally modulated superconducting energy gap, indicating spatial variations of spin states of the Phthalocyanine molecules and their effects on the superconductivity. [1] T. Uchihashi et al., Phys. Rev. Lett. 107, 207001 (2011). [2] J. D. Sau et al., Phys. Rev. Lett. 104, 040502 (2010).

M.M.PI..1
16:30
Authors : F. Pointillart, B. Le Guennic, O. Cador, S. Golhen, L. Ouahab
Affiliations : Universite de Rennes 1, UMR 6226 CNRS-UR1 Institut des Sciences Chimiques de Rennes, 35042, Rennes, France

Resume : Lanthanides-based complexes have greatly contributed to the development of molecular magnetism in the last decade and more particularly in the branch of SMMs. The main reasons are their large magnetic moments associated to their intrinsic large magnetic anisotropy. The splitting of the multiplet ground state of a single-ion in a given environment is responsible of the trapping of the magnetic moment in one direction in SMMs. The ground state multiplet splitting (combination of MJ states) can be extracted from standard magnetic susceptibility measurements through Stevens operators technique. In parallel, theoretical abinitio calculations from the molecular structure also give a direct access to the energy diagram. Furthermore, single-crystal rotating magnetometry provides a unique experimental tool to superimpose the anisotropy tensor, in other words the orientation of the remnant magnetic moment of the molecule magnet, onto the molecular structure. Here again, both experiment and theory can be confronted. In this presentation we will focus on the specific magnetic properties of Tetrathiafulvalene(TTF)-based Dysprosium mononuclear complexes. The structuration is insured by the TTF moieties and the relative orientation of the ligands governs the magnetism. The hydrogen bond effect on the slow magnetic relaxation as well as the enhancement of the dynamic characteristic of the Single Ion Magnet (SIM) by molecular engineering on the -diketonate ancillary ligands will be exposed.

M.M.PI..2
16:30
Authors : Pascal R. Ewen, Jan Sanning, Nikos Doltsinis, Cristian A. Strassert, and Daniel Wegner
Affiliations : Physikalisches Institut and Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, Germany, Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster

Resume : The coupling of molecules at surfaces ranging from the weak (physisorption) to the strong interaction regime (chemisorption) plays a crucial role both in the physical and chemical behavior. Fundamental processes such as conformal changes, dissociation and charge transfer have been observed upon adsorption. A systematic investigation of the adsorption and the electronic structure of slightly differing phosphorescent Pt(II) complexes offers information about the influence of ligands and substituents on their interactions with neighbors and the substrate. We have studied the impact of molecule-surface and intermolecular interactions on the self-assembly and electronic structure of Pt-complex monolayers on Au(111) using scanning tunneling microscopy (STM) and spectroscopy (STS) at low temperature. By determining energies and spatial distributions of several frontier orbitals, we are able to evaluate the impact of coupling and hybridization on the molecular electronic states.

M.M.PI..3
16:30
Authors : J. R. Galan-Mascaros, N. Giménez-Agulló, C. Sáenz de Pipaón, P. Ballester
Affiliations : Institute of Chemical Research of Catalonia (ICIQ); Catalan Institution for Research and Advanced Studies (ICREA)

Resume : Lanthanide-based single-ion magnets (SIMs), as discovered by Ishikawa and co-workers in double-decker (DD) phthalocyanine (Pc) complexes,[1] feature the highest blocking temperatures to exhibit superparamagnetic behavior at the single molecule level, with relaxation barriers as high as 641 cm–1.[2] Due to such striking properties many efforts have been devoted to improve these magnetic properties, with little success. Another aspect that could be improved in these materials is the processing possibilities, since Pc-based DDs are highly insoluble and tend to form aggregates in solution. In this communication, we will present the synthesis, structural and physical characterization of novel lanthanide DD compounds with tetraazaporphyrines. These macrocycles present an identical ring core to Pc, but substituting the aromatic rings by alkyl chains. These complexes show SIM behavior with remarkably high blocking temperatures, and very high solubility in most organic solvent. Furthermore, they can be easily sublimed in mild conditions. [1] N. Ishikawa, M. Sugita, T. Ishikawa, S. Koshihara, Y. Kaizu, J. Am. Chem. Soc.2003, 125, 8694–8695. [2] F. Branzoli, P. Carretta, M. Filibian, G. Zoppellaro, M. J. Graf,| J. R. Galan-Mascaros, O. Fuhr, s. Brink, M. Ruben, J. Am. Chem. Soc.2009, 131, 4387–4396.

M.M.PI..4
16:30
Authors : Mateusz Janeta, Łukasz John*, Sławomir Szafert
Affiliations : University of Wrocław, Faculty of Chemistry, Joliot-Curie 14, Wrocław 50-383, Poland mateusz.janeta@chem.uni.wroc.pl

Resume : Polyhedral oligomeric silsesquioxanes (POSS) are organosilicon compounds with the empirical chemical formula RSiO3/2. Their three dimensionality, high symmetry, and nanometer size make them promising building blocks for nanomaterials. Combining the robust core with the functionalities of the attached organic groups can also change the physical properties of the POSS. A route to a large variety of functionalized POSS compounds by a two-step procedure has been developed. In the first step, an aminofunctionalized alkoxo silane such as 3-aminopropyltriethoxy silane is converted to amino-functionalized POSS (amine-POSS) by a sol–gel process. In the second step, the amine groups of amine-POSS are converted by state-of-the-art amine chemistry. A large number of reactants, including acids halides, esters, anhydrides or acrylates as well as reactants suitable for nucleophilic substitution can be applied. Conversion of an amine-POSS with acids halides leads to an amide-POSS. Amine chemistry can usually be performed under mild conditions, which suppresses degradation and/or cross-linking reactions of the amine-POSS during the conversion. Here we report syntheses and characterization of a new amido-POSS with alkyl and aryl groups. ESI-TOF mass spectrometry and nuclear magnetic resonance spectroscopy (1H, 13C, 29Si, and correlation spectroscopy) have been applied to prove the conversion of an amine-POSS to an amide-POSS.

M.M.PI..5
16:30
Authors : Vigile Trannoy,a Giulia Fornasieri,a Marco Faustini,b David Grosso,b Anne Bleuzen.a
Affiliations : a Institut de Chimie Moleculaire et des Materiaux d'Orsay-UMR 8182, Equipe de Chimie Inorganique, Universite Paris-Sud 11, 91405 Orsay Cedex (France) b Laboratoire de Chimie de la Matiere Condensee de Paris, Universite Pierre et Marie Curie-Paris 6 and CNRS, College de France, 11 place Berthelot 75231 Paris (France)

Resume : Research on smaller and more powerful devices for data storage involves the design of new materials at the nanoscale. Our aim is to develop magnetic nanoparticles with high magnetic anisotropy (oxides or alloys) localized in well-organized nanocraters of a non-magnetic thin film.[1-2] Prussian blue analogues (PBA) were chosen as precursors of the magnetic particles owing to their particularly well-defined structure and chemical composition combined to their versatile chemistry. By tuning PBA chemistry, it should be possible to tune the chemical composition, the structure and therefore the magnetic properties of the derived oxides and alloys. The nanoperforated oxyde thin films were performed using sol-gel chemistry in addition with surfactant micelle templating. PBA growth into the nanocraters has been made layer by layer after a functionalization of the surfaces. The thermal treatment under controlled atmospheres allows the transformation of PBA into oxides or alloys. [3-4] Here we present our first results on the thermal treatment under oxidizing and reductive atmospheres of Co4[Fe(CN)]2.7 PBA confined into the nanocraters of nanoperforated TiO2 thin film. [1] S. Lepoutre, D. Grosso, C. Sanchez, G. Fornasieri, E. Riviere, A. Bleuzen, Advanced Materials 22 (2010) 3992. [2] J. Allouche, D. Lantiat, M. Kuemmel, M. Faustini, C. Laberty, C. Chaneac, E. Tronc, C. Boissiere, L. Nicole, C. Sanchez, D. Grosso, J. Sol-Gel Sci. Technol. 53 (2010) 551. [3] M. Yamada, M. Maesaka, M. Kurihara, M. Sakamoto, M. Miyake, Chem. Commun. 2005) 4851. [4] R. Zboril, L. Machala, M. Mashlan, V. Sharma, Crystal Growth & Design 4 (2004) 1317.

M.M.PI..6
16:30
Authors : Qing Ma1,2, Huarong Li1,2, Baohui Zheng1, Wen Qian1, Guan Luo1, Yuanjie Shu3*
Affiliations : 1Laboratory of Energetic Materials, Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, People's Republic of China 2 School of Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu, China 3 College of Chemistry & Materials Science, Northwest University, Xi'an, 710069, China

Resume : In this work we report the toughening modification of explosive formulation by melt-copolymerization. Molecular dynamics simulations have been used to understand the experimentally observed mechanical behavior of toughened composition B with HTPB-MDI. The effects of interface interactions between a crystalline structure and a melt-cast explosive system were studied. In this work, The hydroxyl-terminated polybutadiene (HTPB) represents the polymer, diphenylmethane diisocyanate (MDI) is the diisocyanate. Two main explosive ingredients of composition B were used, 2,4,6-trinitrotoluene (TNT), which is known for its low melt-point and low sensitivity, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) which is characterized by a high chemical stability. The molecular model is composed of RDX and TNT which represent the main body and Composition B which contain a small amount of polymer. The polymer and crystal were modeled using the force-field UNIVERSAL. Interface structures of RDX and TNT crystal surface together with the HTPB-MDI blend were predicted as well as interfacial binding energies. Bonding energy calculations have been performed in order to investigate the adhesion of the polymer to diverse atomic (hkl) planes of crystals. The ratio of bulk modulus (K) and shear modulus (G) can indicate the plasticity and brittleness. Theoretical calculations confirm that HTPB-MDI/TNT blends are more flexible and ductile. The (200) surface plane of RDX and (010) surface plane of TNT have the largest binding energies and a strongest ability to interact with polymer was observed. We found that the experimental findings could correlate partially with molecular dynamics (MD) simulations.

M.M.PI..7
16:30
Authors : Gianluca Bovo1,2, Irene Braeunlich3, Walter R. Caseri3, Natalie Stingelin2,4, Thomas D. Anthopoulos1,2, Donal D. C. Bradley1,2, Karl G. Sandeman1, Paul N. Stavrinou1,2.
Affiliations : 1 Department of Physics, Imperial College London, London, United Kingdom; 2 Centre for Plastic Electronics, Imperial College London, London, United Kingdom; 3 Department of Materials, ETH Zurich, Zurich, Switzerland; 4 Department of Materials, Imperial College London, London, United Kingdom.

Resume : Under suitable stimuli some materials can exhibit electronic spin crossover (SCO), namely a transition from a low-spin to a high-spin state. Bistability, associated with hysteresis in the switching, can then be used to create a memory device[1]. In the present work we have studied the thermal SCO behaviour of a class of iron(II)-triazole polymers where the chemical properties can be tailored to achieve solubility in common solvents. Two different compounds have been studied, with short and long sidechains. Characterisation of magnetic properties, performed on powders, gels and pellets, serves to highlight the impact of the molecular environment on the SCO. Solution processing of the materials has enabled the preparation of stable thick and thin films, with optical characterisation confirming the retention of SCO properties from the bulk. Furthermore as a first step to deploy these SCO layers inside simple electronic devices, MIM structures (metal-insulator-metal) have been fabricated and tested. Our results show the presence of a thermal hysteresis loop that faithfully reflects the SCO phenomena through the values of the dielectric function around room temperature. Our studies clearly demonstrate that as previously reported for the bulk[2], electrical bistability can also be achieved for thin film (30-40 nm) devices. [1] O. Kahn, Science 1998, 279, 44. [2] A. Bousseksou et al., J. Mater. Chem. 2003, 13, 2069.

M.M.PI..8
16:30
Authors : Dipayan Sen†, Rajarshi Roy†, Nilesh Mazumder†, Uttam Kumar Ghorai‡ and Kalyan Kumar Chattopadhyay†‡
Affiliations : †Thin Film and NanoScience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032, India; ‡School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032, India

Resume : Monolayer planar honeycomb lattices of group IV and group III-V binary compounds and specially engineering their electronic structure have garnered significant research interest in the last decade. Prior reports demonstrated such structures to be usually semiconducting (SiC, GeC, SnC, BN, AlN, GaN, InN, BP, BAs and BSb) with the exception of graphene, which is semimetalic. In the present report, the authors demonstrate, subtle variation of crystal symmetry can invoke a metallic nature in all of these lattices that does not require introduction of defects/ foreign dopants. Ab-initio investigations is used to identify that in such cases, re-ordering of inter-atomic bonds gives rise to additional states near Fermi level that originates mainly due to contribution from p type electrons and whose delocalized nature contributes to the hypothesized metalicity. Furthermore, varying degree of intrinsic spin-polarization is observed for some of the cases (GeC, SnC, AlN, GaN and InN) indicating they might find further specific utilization in spintronics and related fields. In addition to thoroughly exploring and comparing their static stability with pre-existing phases, dynamical stability of such structures is also probed by analyzing their trends of phonon dispersion relation.

M.M.PI..9
16:30
Authors : Hieulle Jeremy and Silly Fabien*
Affiliations : CEA/DSM/IRAMIS/SPEC/HyMN, * fabien.silly@cea.fr

Resume : Controlling the formation of organized structure at the nanometer scale is essential to develop the new generation of electronic components. Perylene imides are promising organic building blocks for photovoltaic application due to there semiconducting nature, and there thermal and photo-stability. Difficulties associated with organic photovoltaic devices include their low quantum efficiency. One origin is usually attributed to organic film defects. Highly ordered organic structure can be tailored taking advantage of molecular self-assembly. To engineer the supramolecular assembly we can use different types of molecular bonds, like covalent bond, hydrogen bond and metal-ligand bond. In our case we selected hydrogen bond, which offer more flexibility for controlling the final arrangement of the supramolecular network, than covalent bond. This enhance flexibility is due to the physical nature of the hydrogen bond. Finally the choice of the hydrogen bond is a good compromise, because it?s relatively weak compare to covalent bond but it?s really strong compare to Van-der-Waals bond. We investigated PTCDI [1,2] thin film on a Au(111) surface, using a scanning tunneling microscope in ultrahigh vacuum. We observed the formation of well organized PTCDI monolayer. At room temperature the PTCDI molecule formed a canted structure. By annealing the surface we were able to form a double and triple-chain PTCDI structure. We observed that molecular contrast was depending of tunneling parameters in that case. This modification of the molecular contrast reveals the formation of new localized electronic states. These new electronic states come from a strong electronic coupling which appears between the PTCDI molecules placed in a side-by-side configuration [3]. 1. M. Mura, X. Sun, F. Silly, and L.N, Kantorovich, Phys. Rev. B 2010, 81, 195412. 2. M. Mura, F. Silly, and L.N, Kantorovich, J. Phys. Chem. C, 2009, 113, 21840. 3. J. Hieulle and F. Silly, J. Mater. Chem. C, 2013, 1, 4536.

M.M.PI..10
16:30
Authors : M. Kulmas (1), O. Feddersen-Clausen (2), M. Y. Bashouti (2), A. Mahmoud (2), S. Christiansen (1, 3)
Affiliations : 1 - Max-Planck-Institut for the Science of Light, 91058 Erlangen, Germany; 2 - ModularFlow, 50939 Köln, Germany; 3 - Helmholtz-Center Berlin, 14109 Berlin, Germany

Resume : Silver wire networks have recently attracted much attention due to promising electrode application in devices such as electronic displays and solar cells for replacing indium tin oxide. However, metallic wire networks can be deposited by using low-cost deposition techniques and exhibit very interesting electro-optical properties. First, we introduce the fabrication process of silver wires grown directly on substrate using photodecomposition of liquid metal-organic precursor at room temperature. Here we studied the experimental parameters (concentration of precursor, irradiations characteristics, etc.) and their influences on the silver wire networks grown from novel metal-organic precursor under UV light. The silver nanowire networks were investigated for producing transparent conductive electrode. Second, we show the optimization of synthesis parameters of silver wire networks and theirs properties such as electrical conductivity, adhesion and transparency. The structural, optical and electrical characterizations were performed by means of scanning electron microscope (SEM), EDX, integrating sphere, 2-probe resistance measurements.

M.M.PI..11
16:30
Authors : C. Kaulen (1), M. Homberger (1), N. Babajani (2), S. Karthäuser (2), U. Simon (1)
Affiliations : (1) Institute of Inorganic Chemistry (IAC) and JARA-FIT, RWTH Aachen University, Germany; (2) Peter Grünberg Institut (PGI-7) and JARA-FIT, Forschungszentrum Jülich GmbH, Germany

Resume : Integration of molecule-capped gold nanoparticles (AuNP) into nanoelectronic devices requires (i) adjustable electrical resistance of the capping molecules, (ii) a reliable contact of the capping molecules to the electrode material[1] and (iii) immobilization of a defined number AuNP into electrode structures. In order to accomplish the latter we investigated the adsorption characteristics of 1,8-mercaptooctanoic acid and 8-amino-1-octanethiol stabilized AuNP (12.3±1.1 nm) on gold/palladium and platinum surfaces. Here, we present how AuNP differentially adsorb to the respective metals, directed by pH, ionic strength, and the composition of the electrolyte chosen[2]. In summary, AuNP with acidic end groups adsorb exclusively on platinum at pH 9 but on gold/palladium at pH 5. AuNP with amine end groups adsorb preferentially on platinum at pH 3. With these findings the integration of single, molecule capped AuNP and even the directed immobilization in nanoelectronic devices gets feasible. [1] S. Karthäuser, J. Phys. Cond. Mat. 23, 013001 (2011) [2] C. Kaulen et al., Langmuir (2014) dx.doi.org/10.1021/la404110y

M.M.PI..12
16:30
Authors : Hyo Jung Kim1, Ji Whan Kim2, Junhyuk Jang3, and Jang-Joo Kim3, Hyun Hwi Lee4,*
Affiliations : 1Pusan National University, Korea;2Samsung Advanced Institute of Technology, Korea;3Seoul National University, Korea;4Pohang Accelerator Lab., Korea;

Resume : The Effect of surface energy on the nano-grain structures of ultra thin copper(II) phthalocyanine (CuPc) films was investigated and their thermal evolution was also analysed by real time grazing incidence small angle X-ray scattering (GI-SAXS) and X-ray reflectivity measurements On hydrophilic Si surface, CuPc film consisted of disk shaped nano-grains of two different sizes. The larger grains showed lateral crystal growth and planarization by thermal annealing, while the smaller grains did not increase in size. The grains formed clusters at high temperature. On hydrophobic Si surface, CuPc nano-grains are more randomly distributed. The crystal size did not increase in size upon thermal annealing. Thermal annealing induced a more random distribution of nano-grains with an increase in roughness, and large islands formed by the coalescence of small grains. The different thermal evolution models of CuPc films based on GI-SAXS analysis are consistent with the different temperature behavior of the hole mobilities of organic field-effect transistor (OFET) devices fabricated on both surfaces. References [1] H. J. Kim, J. W. Kim, H. H. Lee, T.-M. Kim, J.-J. Kim, The Journal of Physical Chemistry Letters 2, 1710 (2011). [2] H. J. Kim, H. H. Lee, J. W. Kim, J. Jang, and J.-J. Kim, Journal of Materials Chemistry 22, 8881 (2012).

M.M.PI..13
16:30
Authors : F. Lupo1, A. Motta1, C. Tudisco 1, F. Bertani 2, A. Gulino1, E. Dalcanale 2, G. G. Condorelli1
Affiliations : 1 Dipartimento di Scienze Chimiche, Università di Catania and INSTM UdR di Catania, v.le A. Doria 6, 95125 Catania, Italy; 2 Dipartimento di Chimica and INSTM UdR di Parma University of Parma Parco Area delle Scienze 17/A, 43124 Parma, (Italy)

Resume : In recent years phthalocyanine have attracted research efforts because their promising application in dye-sensitized solar cells, catalysis, cancer therapy and molecular electronics. In particular, conjucated organic molecules deposited or covalently bonded to surfaces are considered the ultimate limit of electronic devices since they may lead to hybrid heterostructures with new properties. In this communication, hybrid systems of 4-undecenoxyphthalocyanine covalently bonded to Si(100) and porous silicon have been obtained by a thermic hydrosilylation reaction. In a successive step, cobalt (II) complexation of the surface-bonded phthalocyanine was performed directly on the surface by wet chemistry. Each reaction step was studied by X-Ray photoelectron and FT IR spectroscopies. The anchoring geometry of the phthaloctanine were studied combining angle resolved XPS measurement and DFT modelling. In particular N 1s peak was showing different chemical shifts depending on the anchoring geometry and substrate interactions. The efficiency of metalation process of Si bonded phthalocyanine was evaluated from angle resolved XPS measurements. Spectra revealed that the different surface-phthalocyanine interactions observed for flat and porous substrates affected the efficiency of the “in-situ” metalation reaction. On porous silicon the cobalt complexation of the phthalocyanine ring was also confirmed by the disappearance of the band at 3250 cm–1 in the FT-IR spectra.

M.M.PI..14
16:30
Authors : Fernando Novio, Karolina Wnuk, Daniel Ruiz-Molina
Affiliations : ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain; CSIC - Consejo Superior de Investigaciones Cientificas, ICN2 Building, Campus UAB, 08193 Bellaterra (Barcelona), Spain.

Resume : The synthesis at the nanoscale of coordination polymers represents an excellent platform for the fabrication of functional nanostructures. Following this approach, "smart" robust materials can be achieved and their properties can be significantly changed in a controlled manner by different factors. Specifically, the obtaining of size-tunable valence tautomeric nanoparticles (VT-NPs) with low-cost and scalable techniques affords magnetic molecular materials to be used as functional devices at the micro/nanoscale [1]. VT nanoparticles interconvert between two different electronic states with different optical, magnetic and mechanical properties in response to external stimuli such as heat or light irradiation. Our research is focused in the study of synthesis, characterization and stability of polymeric metal- organic systems with switching properties around room temperature. This temperature range makes them feasible for real applications as switchable materials, sensors or storage memories. The critical dependence of the VT behaviour on the local molecular environment [2,3] has determined this study in which the main factors that control the electronic transition were evaluated. Thus, the effect of the chemical composition, packing or crystalline structure were analysed and rationalized to a better understanding of the control on the VT-NPs switchable properties. 1. Angew. Chem. Int. Ed. 47, 1857 (2008). 2. Sci. Rep., 3 , 1708, 1 (2013). 3. Solid State Sci., 11, 793 (2009).

M.M.PI..15
16:30
Authors : Jan Girovsky1, Michele Buzzi2, Christian Wäckerlin1, Dorota Siewert3, Jan Nowakowski1, Peter M. Oppeneer4, Frithjof Nolting2, Thomas A. Jung1, Nirmalya Ballav5, Armin Kleibert2
Affiliations : [1] Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland); [2] Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland); [3] Department of Physics, University of Basel, 4056 Basel (Switzerland); [4] Department of Physics and Astronomy, University of Uppsala, Box 516, S-751 20 Uppsala (Sweden); [5] Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008 (India)

Resume : Spin-bearing metal-organic molecules assembled on magnetic substrates have received significant attention in the last years [1,2]. By adsorption on ferromagnetic substrates magnetic moments can be induced in the molecular species [1]. The induced magnetic moments can be further tuned by i) varying the molecule-substrate interaction via a spacer layer [2],[3] or ii) by external ligands [4]. Most of the established techniques to investigate molecular magnetism are spectroscopic methods lacking spatial resolution. Here, we present the first spectro-microscopy investigation of exchange coupling across the magneto-organic interface exploiting X-ray photo-emission electron microscopy combined with X-ray magnetic circular dichroism. The manganese tetraphenylporphyrin chloride molecules are studied on native and oxygen-treated cobalt surfaces and a chromium spacer layer with increasing thickness on cobalt substrate to modify the molecule-substrate interaction. Such spectro-microscopy correlation can also be used to map the chemical state of ad-molecules with submicrometer resolution and thus provides more conclusive results towards a better understanding of these complex spintronic interfaces [5]. [1] A. Scheybal et al., Chem. Phys. Lett. 411, 214 (2005) [2] D. Chylarecka et al., J. Phys. Chem. Lett. 1, 1408 (2010) [3] C. F. Hermanns et al., Adv. Mater. 25, 3473 (2013) [4] N. Ballav et al., J. Phys. Chem. Lett. 4, 2303 (2013) [5] J. Girovsky et al., Chem. Comm., accepted (2014)

M.M.PI..16
16:30
Authors : Bitam Said 1, Abdelbaki Djebaili 2
Affiliations : 1 Laboratory of Physical chemistry L.P.C - University of Média- Algeria 2 Laboratory of chemistry and environmental chemistry L.C.C.E - University of Batna- Algeria

Resume : Investigation of the geometric and electronic structure of the polyacetylene with substituent’s of different strengths of donor and acceptor functional groups was carried out with 3-21G basis sets, by incorporating The rates of this geometrical isomerization and Arrhenius parameters. In the case of unsubstituted polyacetylene as the reference.. The values of the equilibrium constant for the reaction have also been determined at various temperatures between 300 and 500 K and the value of the energies change calculated. The results demonstrate that the isomerization energies are positive and the barrier heights ∆Ebarrier are expected to be sensitive for the magnitude of substituents effects.

M.M.PI..17
16:30
Authors : Pascal Friedrich, Tobias Neumann, Franz Symalla, Angela Poschlad, Denis Danilov, Ivan Kondov, Velimir Meded, and Wolfgang Wenzel
Affiliations : Pascal Friederich, Tobias Neumann, Franz Symalla, Denis Danilov Velimir Meded, Wolfgang Wenzel: Institute for Nanotechnology, KIT; Angela Poschlad, Ivan Kondov, Steinbuch Center for Computing, KIT

Resume : Transport through thin organic amorphous films, such as those used in OLED and OPV devices, has been difficult to model on using first-principles methods. Nevertheless the carrier mobility depends strongly on the disorder strength and reorganization energy, both of which are significantly affected by the environment of each molecule. Here we present a multi-scale approach to model carrier mobility in which the morphology is generated using DEPOSIT, a Monte Carlo based atomistic simulation approach. From this morphology we extract the sample specific hopping rates, as well as the on-site energies using a fully self-consistent embedding approach to compute the electronic structure parameters which are then used in an analytic expression for the carrier mobility. We apply this strategy to compute the carrier mobility for a set of widely studied molecules and obtain good agreement between experiment and theory for over ten orders of magnitude in the mobility without any adjustable parameters.

M.M.PI..18
16:30
Authors : M. Solorza-Guzman1, F. L. Castillo-Alvarado2, A. Cruz-Torres2, E. Lopez-Chavez3
Affiliations : 1Escuela Superior de Computo del IPN, Av. Juan de Dios Batiz s/n y Av. Miguel Othon de Mendizabal, Lindavista, 07738 Mexico D. F. MEXICO; Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, Edificio 9, 07738 Mexico D.F., MEXICO; 3Programa de Ingenieria Molecular y Nuevos Materiales, Universidad Autonoma de la Ciudad de Mexico Av. Fray Servando Teresa de Mier 99, Col. Centro, Del Cuauhtemoc, C.P 06060 Mexico, D.F., MEXICO.

Resume : Using a methodology based on the quantum version of the Virtual Crystal Approximation (VCA) and the Method of Density Functional Theory on the Generalized Gradient Approximation (GGA) improved by Wu-Cohen (WC) and also for functional Perdew -Burke-Ernzerhof (PBE) GGA theory. We study the magnetic properties of disordered binary alloy Fe1-xCox, with x concentration for the bulk and on the crystallographic plane (110). WE discuss the variation of these magnetic moments and we noticed that our result shows that the 3d band is narrower at the surface according to the surface magnetic moment is greater than the order value.

M.M.PI..19
16:30
Authors : A. Abhervé, J. M. Clemente-Juan, M. Clemente-León, C. J. Gómez-García, M. López-Jordà, E. Coronado
Affiliations : Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/ Catedrático José Beltrán 2, 46980 Paterna, Spain

Resume : In this communication we show three possible strategies to couple a spin crossover cation to high-spin clusters or ferrimagnetic extended networks. The first strategy consists on covalently linking a spin-crossover complex to a magnetic ion. Thus, the tridentate ligand bis(pyrazol-1-yl)pyridine (bpp) have been functionalized with a carboxylate group, and reaction of this ligand with FeII have led the formation of a new spin-crossover complex, that shows an abrupt spin transition with a T1/2 of 380 K and LIESST effect [1]. The presence of the carboxylate groups has allowed the preparation of a nonanuclear cluster. The second strategy is the preparation of a hybrid ionic compound with the spin-crossover cation inserted into a bimetallic anionic extended network from anilate and its derivatives (C6O4X22-, X=Cl, Br). A family of compounds formed by FeII and FeIII spin-crossover cations inserted into ferrimagnetic extended networks has been obtained. Finally, as a third strategy, tetradentate imidazolyl-based ligands have been used. Their reaction with FeIII and SCN- has led to tetranuclear, hexanuclear or octanuclear FeIII clusters [2]. The nuclearity of the cluster can be controlled by choosing the counterion. Crystal structures and magnetic properties of compounds obtained with these three strategies are presented in this communication. [1] A. Abhervé et al., Dalton Trans., in press. [2] A. Abhervé et al., New J. Chem., in press.

M.M.PI..20
16:30
Authors : Srikanth Chakaravarthy 1,2, Alain Bulou 2, Mauricio Ortega Lopez 3, Jaime Santoyo Salazar 4
Affiliations : 1 Programa de Doctorado en Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 2 l'Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, Université du Maine, 72085 Le Mans Cedex 9 France 3 Sección de Electronica y Estado Solido, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 4 Departmento de Fisica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México

Resume : This work reports the colloidal synthesis of silver telluride (Ag2Te) nanoparticles by adapting a predefined procedure. As synthesized materials were rinsed several times with deionized water and anhydrous ethanol, and preserved in toluene. All the characterizations were performed on the drop-casts inks on suitable substrate. The crystallinity and phase group were assessed by x-ray diffraction (XRD) technique. Field emission scanning electron microscope (FESEM-EDX) analyses reveal nearly stoichiometric composition and self-assembled nature of the nanocrystals. Size, shape, crystallinity and dispersity were studied by high resolution transmission electron microscopy (HRTEM), which reveals that the nanoparticles are of nearly spherical and cubicle in morphology and in the size range of 5-10 nm resulted in different batches. Results will be discussed in detail.

M.M.PI..21
16:30
Authors : Srikanth Chakaravarthy 1,2, Alain Bulou 2, Mauricio Ortega Lopez 3, Jaime Santoyo Salazar 4, Marie-Pierre Crosnier Lopez 2
Affiliations : 1 Programa de Doctorado en Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 2 l'Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, Université du Maine, 72085 Le Mans Cedex 9 France 3 Sección de Electronica y Estado Solido, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 4 Departmento de Fisica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México

Resume : Colloidal synthesis of lead telluride nanocrystals have been carried out by adapting a predefined procedure. The crystallinity and phase group were assessed by x- ray diffraction (XRD) technique. Qualitative analyses of the sample were performed using Raman spectroscopy. The interaction between oleic acid and PbTe nanocrystals are analyzed by subjecting the samples to Fourier transform infrared spectrometry. Field emission scanning electron microscopic analyses reveal lead rich stoichiometric composition and self-assembled nature of the nanocrystals both on silicon substrate as well as on carbon tape. High resolution transmission electron microscopy analyses reveal the high crystallinity and monodispersity of synthesized nanoparticles. Size ranging from 6.5 to 16 nm were obtained in different synthesis conditions. The long term environmental stability of a selected batch of nanocrystals in the ambient condition was also studied by subjecting the samples to XRD, Raman and HRTEM at different intervals from the date of synthesis. It is inferred that the nanocrystals retained its crystallinity, morphology and composition even after 20 months from the date of synthesis. Results will be discussed in detail.

M.M.PI..22
16:30
Authors : Srikanth Chakaravarthy 1,2, Alain Bulou 2, Mauricio Ortega Lopez 3, Jaime Santoyo Salazar 4
Affiliations : 1 Programa de Doctorado en Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 2 l'Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, Université du Maine, 72085 Le Mans Cedex 9 France 3 Sección de Electronica y Estado Solido, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México 4 Departmento de Fisica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), No. 2508 Av. IPN, Col. San Pedro Zacatenco, C.P. 07360 Distrito Federal, México

Resume : Green synthesis and characterization of silver telluride (Ag2Te) nanoparticles have been carried out for the first time to best of our knowledge. We present the synthesis process, structural, morphological and compositional characterizations of the nanoparticles. A predefined process was adapted by replacing 1-dodecanethiol with powders of curcuma longa, a natural reducing agent. The as-synthesized materials were washed several times with deionized water and anhydrous ethanol, and re-dispersed in toluene. Further investigations have been carried out on drop-cast films deposited onto a chosen substrate. Field emission scanning electron microscope (FESEM-EDX) analyses reveal nearly stoichiometric Ag2Te nanomaterials. Transmission electron microscopy (TEM) reveals that most of the prepared Ag2Te nanoparticles are within a size range of 6-10 nm, along with some large nanoparticles of about 15-20 nm range. Optical properties and interaction of natural agent with the nanoparticle were also studied by subjecting the Ag2Te to Absorption, FTIR and Raman spectroscopy techniques. Results will be discussed in detail.

M.M.PI..23
16:30
Authors : Svetlana Klyatskayaa, M. Rubena, b, M. Urdampilletac, R. Vincentc, M. Ganzhornc, W. Wernsdorfer,c
Affiliations : aInstitute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany bIPCMS-CNRS UMR 7504, Université de Strasbourg, 23 Rue du Loess, 67034 Strasbourg, France cInstitut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France

Resume : Metal phthalocyanines (MPcn, n=1,2) are widely employed in the field of molecular materials mainly due to their exceptional stability and interesting physical properties, i.e. intense absorption in almost all the visible region and high polarizability, derived from their delocalized electronic system. Moreover, the chemical versatility of MPcn makes possible the introduction of different types of metals in their central cavity and their peripheral functionalization, thus allowing the modulation of their electronic properties. One of the unique properties of phthalocyanines is their ability to form bis-phthalocyanine complexes with trivalent lanthanide ions - LnPc2 - exhibiting single-molecule magnet (SMM) behaviour. At low temperatures, quantum magnets of the TbPc2 family are characterized by a large magnetic moment in the ground state, a high zero-field splitting due to their large magnetic anisotropy, slow relaxation of the magnetization and a strong hyperfine coupling 1. In addition, their magnetic properties show a very large spectrum of quantum physics phenomena. We will present an overview on the possibilities of supramolecular design using lanthanide complexes of phthalocyanines carried out by the group targeting the self-assembly of spintronic devices. To increase the non-invasive attachment to sp2-carbon materials at very low concentrations, the TbPc2 SMMs used herein were modified by introducing one pyrene group and six hexyl groups into one of the two Pc rings 2. Supramolecular techniques were used to position magnetic molecules in defined device environments where single-spin addressing leads to the observation of magnetoresistive effects 3-6. The demonstrated possibility of manipulating spins at the single molecule limit opens a completely new world to molecular spintronics, where memory, logic and possibly quantum logic may be integrated. REFERENCES 1. Ishikawa, N. Polyhedron, 26, 2007, 2147-2153. 2. Klyatskaya, S., Galán Mascarós, J.-R.; Bogani, L., Hennrich, F., Kappes, M., Wernsdorfer, W.; Ruben, M. J. Am. Chem. Soc. 131(42), 2009, 15143-15151. 3. Candini, A., Klyatskaya, S., Ruben, M., Wernsdorfer, W., Affronte, M. Nano Letters, 11(7), 2011, 2634-2639. 4. Urdampilleta, M., Klyatskaya, S., Cleuziou, J.-P., Ruben, M., Wernsdorfer, W. Nature Materials, 10(7), 2011, 502-506. 5. Vincent, R., Klyatskaya, S., Ruben, M., Wernsdorfer, W., Balestro F. Nature, 488, 2012, 357–360. 6. Ganzhorn, M., Klyatskaya, S., Ruben.M., Wernsdorfer, W. Nature Nanotechnology 8, 2013, 165-169.

M.M.PI..24
16:30
Authors : Bernhard Schäfer, A., Ivan Šalitroš, A., Mario Ruben, A. B.
Affiliations : A. Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe, Germany B. Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg, France

Resume : Spin transition (ST) compounds have increasingly moved into the focus of scientific interest due to their potential applicability in molecular devices. The pronounced bistability between high spin (HS) and low spin (LS) states is a very attractive property of ST materials and it was proposed to use such compounds as active units for information technology applications. However, in order to process the ST compounds into functional devices it is required that the material shows abruptness of transition, wide thermal hysteresis behavior, stability, and room temperature transition temperature.[1] We will present the synthesis and the magnetic properties of a new family of spin transition complexes employing different methods to probe the structural and magnetic properties of the prepared systems. [1] a) O. Kahn, C. Jay Martinez, Science 1998, 279; b) M. Cavallini, I. Bergenti, S. Milita, G. Ruani, I. Šalitroš, Z. Qu, R. Chandrasekar, M. Ruben Angew. Chemie 2008 47, 45, 8596; c) B. Schäfer, C. Rajnak, I. Salitros, O. Fuhr, D. Klar, C. Schmitz-Antoniak, H. Wende, M. Ruben Chem. Commun. 2013, 49, 10986.

M.M.PI..25
16:30
Authors : Peter Robaschik 1, Michael Fronk1, Svetlana Klyatskay 2, Mario Ruben 2,3, Dietrich R.T. Zahn1, Georgeta Salvan 1
Affiliations : 1 TU Chemnitz, 09126 Chemnitz, Germany 2 KIT, 76344 Eggenstein-Leopoldshafen, Germany 3 ICPMS, 67034 Strasbourg, France

Resume : The single molecule magnet (SMM) terbium(III) bis(phthalocyanine) is considered as a promising candidate for spintronic applications. In this work, films with thicknesses below 100 nm were deposited by organic molecular beam deposition on ferromagnetic, in-plane magnetized Co films. The (magneto-)optical properties were investigated by means of variable angle spectroscopic ellipsometry (VASE) and magneto-optical Kerr effect (MOKE) spectroscopy at room temperature. The molecular orientation was determined from the degree of uniaxial anisotropy of the optical constants and from the amplitude of the magneto-optical Voigt constant. The magnetic coupling of the molecules with the substrate is investigated by MOKE magnetometry in the temperature range from 4 K to 300 K.

M.M.PI..26
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Spin-effect materials : Frank Schramm
08:30
Authors : Herre van der Zant
Affiliations : Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

Resume : By merging the fields of molecular magnetism, molecular electronics and nanotechnology, we fabricate planar three-terminal nanodevices containing individual magnetic molecules. Source and drain electrodes are made of Au or of (multi-layered) graphene. A third gate electrode allows the modification of charge transport independently from the source/drain electrodes. In this way, a spin transistor is built in which the electric current through the individual magnetic molecule. The molecular complexes of interest are single-molecule magnets (SMMs) and spin-crossover compounds [1]. At cryogenic temperatures Coulomb blockade is generally observed including finer details such as Kondo correlations and excited states [2]. In a Fe-4 SMM based transistor, we observe features that confirm the high-spin state and find Kondo behavior and a zero-field splitting that depends on the redox state; in the charged state the molecule turns out to be a better magnet [3]. Using an in-situ sample rotator, direct observation of magnetic anisotropy has been demonstrated [4]. Work supported by FOM and through the FET EU FP7 program (ELFOS) and an ERC advanced grant (Mols@Mols); email: h.s.j.vanderzant@tudelft.nl. [1] V. Meded et al., Phys. Rev. B 83 (2011) 245115; F. Prins et al. Adv. Mat. 23 (2011) 1545. [2] H.B. Heersche et al., Rev. Lett. 96 (2006) 206801; E.A. Osorio et al., Nano Letters 10 (2010) 105; J.M. Thijssen and H.S.J. van der Zant, Phys. stat. sol. (b) 245 (2008) 1455-1470. [3] A. Zyazin et al. Nano Letters 10 (2010) 3307. [4] E. Burzurí, A.S. Zyazin, A. Cornia and H.S.J. van der Zant, Phys. Rev. Lett. 109 (2012) 147203.

M.M.IV..1
09:00
Authors : Christian Wäckerlin1, Jan Nowakowski1, Shi-Xia Liu2, Michael Jaggi2, Jan Girovsky1, Dorota Siewert1, Aneliia Shchyrba3, Tatjana Hählen1, Armin Kleibert4, Peter M. Oppeneer5, Frithjof Nolting4, Silvio Decurtins2, Thomas A. Jung1, Nirmalya Ballav6
Affiliations : [1] Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland; [2] University of Bern, Department of Chemistry and Biochemistry, Bern, 3012, Switzerland; [3] University of Basel, Department of Physics, Basel, 4056, Switzerland; [4] Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland; [5] Department of Physics and Astronomy, University of Uppsala, Box 516, S-751 20 Uppsala, Sweden; [6] Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India;

Resume : Metal-organic complexes possessing a magnetic moment adsorbed on ferromagnetic substrates are exciting systems which allow to study the magnetism of individual magnetic ions in the proximity of ferromagnetic substrates [1]. The molecular spin moment which is induced by the interaction of the molecule with the substrate can be modified by an optional external ligand coordinating with its metal center [2]. In our most recent work we employ synthetically directed self-assembly [3] to fabricate a highly ordered, two-dimensional chessboard-like structure of Fe and Mn spin-system which is exchange-coupled to a suitable ferromagnetic substrate [4]. On-surface magneto-chemistry [5] is then used to reversibly control the magnetic moments in this Fe-Mn-Fe spin-chessboard lattice via selective response to ammonia ligand. We combine Scanning Tunneling Microscopy (STM) with X-ray Absorption Spectroscopy and X-ray Magnetic Circular Dichroism experiments to unravel local and spatially averaged and element-specific information of the electronic and magnetic properties of the 2-D spin array. High resolution STM also resolves the strength of the interaction between the ammonia ligand and molecule’s metal center. [1] A. Scheybal et al., Chem. Phys. Lett. 411, 214 (2005) [2] C. Wäckerlin et al., Chem. Scie. 3, 3154 (2012) [3] K. W. Hipps et al., J. Am. Chem. Soc. 124, 2126 (2002) [4] C. Wäckerlin et al., Adv. Mater. 25, 2404 (2013) [5] N. Ballav et al., J. Phys. Chem. Lett. 4, 2303 (2013)

M.M.IV..2
09:15
Authors : Igor Beljakov, Velimir Meded, Franz Symalla, Karin Fink, Sam Shallcross, Mario Ruben and Wolfgang Wenzel
Affiliations : Igor Beljakov, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany; Velimir Meded, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany; Franz Symalla, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany; Karin Fink, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany; Sam Shallcross, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany; Mario Ruben, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany; Wolfgang Wenzel, Institute of Nanotechnology (INT), KIT, Karlsruhe, Germany

Resume : Spin crossover (SCO) phenomena have been studied for years, motivated by technological and fundamental interest, such as applications in magnetic storage devices or spintronics. SCO has been observed in crystals of 3d transition metal (TM) metal-organic complexes, where the magnetic moment of the metal center in a ligand field can be externally switched between low-spin (LS) and high-spin (HS) state, e.g. by temperature, light, or magnetic field. SCO induced by external electric fields was recently observed on single molecule level opening for new possibilities in spintronics, or quantum computing, albeit, so far, only at low temperatures. Here we present 5d-TM adsorption on graphene nanoflakes, interpolating between the zero-dimensional limit of a TM-decorated benzene and the two-dimensional limit of graphene, by means of density functional theory calculations. For several 5d TMs adsorbed on a variety of nanoflakes, we find multiple adsorption minima corresponding to differe nt spin states, absent in the zero- and two-dimensional limit. We show that the barrier between the states is sufficient to stabilize the HS or the LS state at finite temperature and it is possible to reversibly switch between them with an electric field. The TM-decorated flake undergoes a change in magnetic anisotropy upon spin crossover, which facilitates read-out of the spin state and, thus, acts as fully controlled single-ion magnetic switch with many potential technological applications.

M.M.IV..3
09:30
Authors : E. Saitoh (1)-(3)
Affiliations : (1) WPI-AIMR, Tohoku University, Sendai 980-8577, Japan; (2) Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan; (3)ASRC, Japan Atomic Energy Agency, Tokai 319-1195, Japan

Resume : Spin current, a flow of electrons? spins in a solid, is the key concept in spintronics that will allow the achievement of efficient magnetic memories, computing devices, and energy converters. I here review phenomena which allow us to use spin currents in insulators [1]: inverse spin-Hall effect [2,4], spin pumping, and spin Seebeck effect [4-6]. We found that spin pumping and spin torque effects appear at an interface between an insulator YIG and Pt. Using this effect, we can connect a spin current carried by conduction electrons and a spin-wave spin current flowing in insulators. We demonstrate electric signal transmission by using these effects and interconversion of the spin currents [1]. Seebeck effect (SSE) is the thermal spin pumping [5]. The SSE allows us to generate spin voltage, potential for driving nonequilibrium spin currents, by placing a ferromagnet in a temperature gradient. Using the inverse spin-Hall effect in Pt films, we measured the spin voltage ge nerated from a temperature gradient in various ferromagnetic insulators. This research is collaboration with K. Ando, K. Uchida, Y. Kajiwara, S. Maekawa, G. E. W. Bauer, S. Takahashi, and J. Ieda. REFERENCES [1]. Y. Kajiwara & E. Saitoh et al. Nature 464 (2010) 262. [2] E. Saitoh et al., Appl. Phys. Lett. 88 (2006) 182509. [3] A. Ando & E. Saitoh et al., Nature materials 10 (2011) 655 -659. [4] K. Uchida & E. Saitoh et al., Nature 455 (2008)778. [5] K. Uchida & E. Saitoh et al., Nature materials 9 (2010) 894 - 897. [6] K. Uchida & E. Saitoh et al., Nature materials 10 (2011) 737-741.

M.M.IV.4
10:00 Morning Break    
 
Charge transport in devices : Bernhard Schäfer
10:30
Authors : Luis E. Hueso, Marco Gobbi, Xiangnan Sun, Amilcar Bedoya-Pinto, Felix Casanova
Affiliations : CIC nanoGUNE; IKERBASQUE Basque Foundation for Science

Resume : Materials based on carbon have recently caught the attention of spintronics, and significant efforts are being made towards their integration in this field. One of their most attractive aspects for spintronic applications is the weakness of their spin scattering mechanisms, implying that the spin polarization of the carriers can be maintained for a very long time in these materials. Noticeably, spin relaxation times of miliseconds have been reported by different techniques, these values exceeding by orders of magnitude the characteristic times detected in inorganic materials. In this talk, I will present results with a prototypical spintronic device (the spin valve), in which a molecular active layer was sandwiched between two ferromagnetic materials. I will show how two very different molecules, namely C60 fullerene and bathocuproine or BCP, are capable or maintaining the coherence of the spin of the injected carriers for more than 60 nm at room temperature. In the case of the fullerene, the room temperature magnetoresistance data is consistent with a multistep tunneling regime. In the case of the BCP, we highlight the differences between spin tunneling and transport in molecular levels. The chemical stability of this molecule, even under ambient conditions, could make it very attractive for potential molecular spintronic We expect our results to be reproduced by other molecular semiconductors, opening novel pathways for the further development of molecular spintronics.

M.M.V..1
11:00
Authors : Yutaka Wakayama, Ryoma Hayakawa, Toyohiro Chikyow
Affiliations : International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS)

Resume : A main purpose is to develop electron-tunneling devices by taking advantages of molecular functions. A key point is to integrate organic molecules into Si-based device architecture for practical device development. Here, we discuss a fundamental mechanism, multi-level control and optical switching of electron tunneling through molecules. In general, quantum dots for the tunneling devices should be well controlled. In fact, size uniformity is important for controlling threshold voltage (Vth) for electron tunneling. To meet these requirements, we adopted organic molecules as quantum dots. First, C60 molecules were embedded in a Au/Al2O3/C60/SiO2 multilayer to form a double-tunneling junction on a Si substrate, in which C60 molecules work as intermediate electrodes. Staircases in a current-voltage curve were observed, and we elucidated that the observed staircases can be attributed to resonant tunneling through the empty and occupied energy levels of the molecules. These results indicate that the Vth can be tuned precisely by designing molecular structure. Furthermore, these results have been expanded to multi-level tunneling and optically controlled-tunneling by using multiple heterogeneous phthalocyanine molecules and photochromic molecules, respectively.

M.M.V..2
11:15
Authors : Jorge Trasobares, Ragavendran Sivakumarasamy, Claire Whal, Alexis Vlandas, Thierry Martin, J.-P. Nys, Dominique Vuillaume, Didier Théron, Nicolas Clément
Affiliations : Jorge Trasobares; Ragavendran Sivakumarasamy; Claire Whal; Alexis Vlandas; J.-P. Nys; Dominique Vuillaume; Didier Théron; Nicolas Clément, Institut d'électronique de microélectronique et de nanotechnologie, CNRS, Villeneuve d'Ascq (France). Thierry Martin, Centre de Physique Théorique, CNRS, Marseille (France).

Resume : Electrochemical sensors or biosensors use redox (e.g. ferrocene) probes attached to an interrogating electrode. Progresses in electrochemical atomic force microscopy have permitted measurement of redox signal at single gold nanoparticle level. However, specific mediator-tethered amplification mechanisms used with this technique are not compatible with lab-on chip approaches.Here, we present electrochemical studies on a large array of ferrocene-coated nanoelectrodes (nanoparticles as small as 8 nm) and demonstrate measurement of cyclic voltamograms (CyV) arising from hundreds of ferrocenyl undecanethiol molecules per nanoelectrode without any amplification. Quantitative analysis of results allows extraction of the average number of molecules per dot, show different organization phases depending on dot dimension/redox molecules dilution, and extraction of the g-parameter used to evaluate interaction between molecules. Interestingly, a recent theoretical prediction in molecular electronics (electrolyte replaced by a top electrode) has shown that cooperative effects could be evaluated from the line shape of conductance histograms. We used this array of thousands of nanoelectrodes to generate such histograms using a Conducting AFM tip as a top electrode. From fits in histograms shapes (with asymmetry), cooperative effects and different molecular phases are discussed and compared with CyV results. These results open perspectives for sensors with a single redox molecule per dot.

M.M.V..3
11:30
Authors : Pierre Seneor, Marta Galbiati, Marie-Blandine Martin, Sophie Delprat, Bruno Dlubak, Sergio Tatay, Clément Barraud, Eric Jacquet, Cyrile Deranlot, K. Bouzehouane, A. Anane, Albert Fert, Richard Mattana and Frédéric Petroff
Affiliations : Unité Mixte de Physique CNRS/Thales & Université de Paris Sud 91767 Palaiseau, France

Resume : Spintronics is a paradigm focusing on spin as the information vector in fast and ultra-low-power non volatile devices such as the new STT-MRAM. Beyond its widely distributed application in data storage it aims at providing more complex architectures and a powerful beyond CMOS solution. Very recently, molecular spintronics, a rising research field at the frontier between organic chemistry and spintronics, has opened novel and exciting opportunities in terms of functionalities and performances for spintronics devices. Beyond, plasticity and low cost, carbon based materials such as graphene and nanotubes were first seen as very promising for spintronics devices due to their expected long spin lifetime and potential for becoming the ultimate spintronics media. It was only very recently that new spintronics tailoring opportunities that could be brought by molecules and molecular engineering were unveiled. We will present experimental results unveiling promising uses of carbon based molecules for spintronics. We will show that while graphene has potential for unprecedented highly efficient spin information transport [1], the molecular structure, the local geometry at the molecule-electrode interface and more importantly the ferromagnetic metal/molecule hybridization can strongly influence interfacial spin properties going from spin polarization enhancement to its sign control in spintronics devices [2]. Spin dependent transport measurements on ferromagnet/molecules/ferromagnet magnetic tunnel junctions where molecules are organic semiconductors (Alq3) or self-assembled monolayers [3] highlighting the crucial role of the interface will be presented. In addition we will show that a thin graphene passivation layer can prevent the oxidation of a ferromagnet, enabling its use in novel humide/ambient low-cost processes for spintronics devices for molecular spintronics. We will show that graphene coating doesn’t spoil the highly surface sensitive spin current polarizer/analyzer behavior, but more importantly adds a new enhanced spin filtering property [4]. This work was funded through the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement 263104 and 285275. REFERENCES [1] B. Dlubak et al., Nature Physics 8, 557 (2012); P. Seneor, et al., MRS Bulletin 37, 1245 (2012) [2] C. Barraud et al., Nature Physics 6, 615 (2010) [3] M. Galbiati, Adv. Mater. 24, 6429 (2012), S. Tatay et al., ACS Nano 6, 8753 (2012) [4] B. Dlubak et al., ACS Nano 6, 10930 (2012); R. Weatherup, et al., ACS Nano 6, 9996 (2012)

M.M.V..4
12:00 Lunch Break    
 
Spintronics : Velimir Meded
13:30
Authors : Xiao HU
Affiliations : International Center for Material Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Japan

Resume : A topological state called antiferromagnetic topological insulator characterized by simultaneous nonzero charge and spin Chern numbers is possible for electrons on honeycomb lattice. This state is realized through a full band engineering using a staggered electric potential, antiferromagnetic exchange field and intrinsic spin-orbit coupling to control the three degrees of freedom: spin, sublattice and valley. With first principles calculation we confirm that one can achieve this novel state by inserting a [111] mono-atomic layer of gold (Au) into a Mott insulator LaCrO_3 of perovskite structure and applying an electric field along [111] direction. This material is ideal for spintronics applications, since a finite sample provides a spin-polarized quantized edge current, robust to both nonmagnetic and magnetic defects, with the spin polarization reversible by the electric field. The total magnetization is compensated to zero, and thus the system can be considered as a topological half-metallic antiferromagnet. This work is a collaboration with Q.-F. Liang and L.-H. Wu. It was supported by the WPI Initiative on Materials Nanoarchitectonics, MEXT, Japan, and partially by the Grants in Aid for Scientific Research (No. 22540377), JSPS, and Innovative Area ?Topological Quantum Phenomena? (No.25103723), MEXT of Japan.

M.M.VI..1
14:00
Authors : Jose Sanchez Costaa,d Santiago Rodriguez Jimeneza, Gavin A. Craiga, Olivier Roubeaub, Christine Beaversc, Simon J. Teatc, Azzedine Bousseksou,d and Guillem Aromíaa
Affiliations : aDepartament de Química Inorgànica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain. bInstituto de Ciencia de Materiales de Aragón (ICMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009, Zaragoza, Spain. cAdvanced Light Source, Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA dLaboratoire de la Chimie de Coordination. 205, route de Narbonne, 31077 Toulouse Cedex 4, France

Resume : Nanoporous materials have exceptional characteristics that confer them important potential technological applications such as molecular sieves, sensors, magnetism and catalysis[1]. Those materials have recently experienced a renewed interest since the discovery of a new class of flexible porous materials, which contrast with the well-explored rigid porous materials. These materials defined as soft porous crystals[2] may respond to external stimuli such as light, a magnetic field or even the interaction with some molecules, keeping their crystallinity and porosity intact. Moreover, spin-crossover (SCO) properties have been introduced in such porous materials with the aim of reaching room temperature applications[3]. SCO involves a change in the electronic configurations of molecules by applying an external perturbation such as temperature, pressure, or light irradiation. Furthermore, SCO is a molecular phenomenon, which is accompanied by dramatic and readily detectable changes of macroscopic properties (color, crystal size and magnetism). In some cases, the central cavity of these ligands, based on the well-known “bpp” moiety, is suited for accessing Fe(II) complexes exhibiting SCO, while the external groups can play other chemical or structural roles.[4] In this presentation we described the research work concerning the sensor activity of a new non-porous SCO material that can act as a soft porous molecular framework in which the molecular bistability is associated to a solvent absorption-desorption process in a reversible way above room temperature. This work has a continuation research work focused on the nano-patterning and nano-structuration of such materials for further studying their exciting physico-chemical properties. The controlled solvent exchange for this sample would without any doubt be of great benefit in many practical applications.[1] D. Maspoch, D. Ruiz-Molina and J. Veciana, Chem Soc Rev, 2007, 36, 770-818. [2] S. Horike, S. Shimomura and S. Kitagawa, Nature Chemistry, 2009, 1, 695-704. [3] A. Bousseksou, G. Molnar, L. Salmon, W. Nicolazzi, Chemical Society Reviews 2011, 40, 3313-3335 [4] G. A. Craig, J. Sanchez Costa, O. Roubeau, S. J. Teat and G. Aromi, Chem-Eur J, 2011, 17, 3120-3127.

M.M.VI..2
14:15
Authors : Marc Warner, Salahud Din, Igor S. Tupitsyn, Gavin W. Morley, A. Marshall Stoneham, Jules A. Gardener, Zhenlin Wu, Andrew J. Fisher, Sandrine Heutz, Christopher W. M. Kay, Gabriel Aeppli
Affiliations : Harvard University, Imperial College London, University of British Columbia, Warwick University, University College London, Harvard University, Imperial College London, University College London, Imperial College London, University College London, University College London.

Resume : Organic semiconductors are studied intensively for applications in electronics and optics, and even spin-based information technology, or spintronics. Fundamental quantities in spintronics are the population relaxation time (T1) and the phase memory time (T2): T1 measures the lifetime of a classical bit, in this case embodied by a spin oriented either parallel or antiparallel to an external magnetic field, and T2 measures the corresponding lifetime of a quantum bit, encoded in the phase of the quantum state. Here we establish that these times are surprisingly long for a common, low-cost and chemically modifiable organic semiconductor, the blue pigment copper phthalocyanine, in easily processed thin-film form of the type used for device fabrication. At 5 K, a temperature reachable using inexpensive closed-cycle refrigerators, T1 and T2 are respectively 59 ms and 2.6 ms, and at 80 K, which is just above the boiling point of liquid nitrogen, they are respectively 10 ms and 1 ms, demonstrating that the performance of thin-film copper phthalocyanine is superior to that of single-molecule magnets over the same temperature range.

M.M.VI..3
14:30
Authors : S. Mizukami, A. Sugihara, Q. L. Ma, X. M. Zhang, T. Miyazaki
Affiliations : WPI-Advanced Institute for Materials Research, Tohoku University

Resume : D022 Mn3Ga alloy is a novel tetragonal ferrimagnet with a large uniaxial magnetic anisotropy and large spin polarization [1]. We demonstrated a large perpendicular magnetic anisotropy (PMA) as well as small spin damping in the epitaxial alloy films [2-4]. Recently, we predicted that another new material, D022 Mn3Ge, was a half-metallic ferrimagnet along c-axis with a large PMA, small magnetization and small spin damping. We also succeeded to grow good epitaxial Mn3+xGe films with large PMA and small magnetization [5]. These properties are well suitable to 10 Gbit class spin-transfer-torque magnetic random access memory (STT-MRAM) applications. On the other hand, the large PMA and small magnetization of these materials induce large internal magnetic field, which leads very fast spin angular momentum precession [3,6]. We observed the coherent spin precession with frequency more than 0.3 THz in D022 Mn3-xGa using a fs pump-probe optics with magnetic field of 2 Tesla, which is the fastest coherent spin precession observed in metallic magnets and could be applied to THz spintronics devices. [1] B. Balke et al., Appl. Phys. Lett. 90, 152504 (2007). [2] F. Wu et al., Appl. Phys. Lett. 94, 122503 (2009). [3] S. Mizukami et al., Phys. Rev. Lett. 106, 117201 (2011). [4] S. Mizukami et al., Phys. Rev. B 85, 014416 (2012). [5] S. Mizukami et al., Appl. Phys. Express 6, 123002 (2013); A. Sugihara et al, submitted. [6] S. Mizukami et al., Appl. Phys. Lett. 103, 142405 (2013).

M.M.VI..4
15:00 Afternoon Break    
 
Single Molecule Magnets : Svetlana Klyatskaya
15:30
Authors : Wolfgang Wernsdorfer
Affiliations : Institut Neel, CNRS, BP 166, 38042 Grenoble, France

Resume : We will address the field called molecular quantum spintronics, which combines the concepts of spintronics, molecular electronics and quantum computing. Various research groups are currently developing low-temperature scanning tunnelling microscopes to manipulate spins in single molecules, while others are working on molecular devices to read and manipulate the spin state and perform basic quantum operations. The talk will discuss this - still largely unexplored - field and present our first results. For ex., we have built a novel spin-valve device in which a non-magnetic molecular quantum dot, consisting of a single-wall carbon nanotube contacted with non-magnetic electrodes, is laterally coupled to a TbPc2 molecular magnet. The localized magnetic moment of the SMM led to a magnetic field-dependent modulation of the conductance in the nanotube with magnetoresistance ratios of up to 300% below 1 K. Using a molecular spin-transistor, we achieved the electronic read-out of the nuclear spin of an individual metal atom embedded in a single-molecule magnet (SMM). We could show very long spin lifetimes (> 10 seconds). Using the hyperfine Stark effect, which transforms electric fields into local effective magnetic fields, we could not only tune the resonant frequency by several MHz, but we also performed coherent quantum manipulations on a single nuclear qubit faster than a μs by means of electrical fields only, establish the individual addressability of identical nuclear qubits.

M.M.VII..1
16:00
Authors : Barbara Brena,1 Heike C. Herper,1 Sumanta Bhandary,1 David Klar, 2 Heiko Wende,2 Olle Eriksson,1 Biplab Sanyal 1
Affiliations : 1: Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden 2: Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg, Germany

Resume : Searching for novel and reversible mechanisms for magnetic switching, attention has been dedicated to the interaction of organic macrocyles like porphyrins and phthalocyanines containing divalent 3d transition metals with magnetic substrates. We have studied the chemisorption of Fe porphyrins (FeP) and of Fe phthalocyanines (FePc) on Co(001) by means of first principles Density Functional Theory with the GGA+U method, including van der Waals dispersion forces. Two different adsorption mechanisms were identified for the two molecules, although both cases resulted in a ferromagnetic coupling. The adsorbed FePc's maintain the same magnetic moment of about 2 μB of the gas phase, while upon adsorption the magnetic moment of the FeP's increases up to about 4 μB. We could couple the change to high spin (S=2) in FeP to the stretching of the Fe-N molecular bonds to more than 2.04Å produced by the strong chemical interaction with the substrate. The same results have been obtained for FeP chemisorbed on Ni(001), Ni(110) and Ni(111). In addition, we have analysed the interaction of FePc with a c(2X2)O covered Co(001) surface, obtaining an antiferromagnetic coupling of the molecules with the Co substrate, and a weaker coupling than in the absence of the O interlayer. The theoretical findings related to the magnetic coupling and to the adsorption structure of the molecules were also confirmed by Fe L edge and N K edge experimental absorption spectroscopy.

M.M.VII..2
16:15
Authors : M. Golecki,a J. Lach,a A. Jeremies,a F. Lungwitz,b M. Fronk,b P.Robaschikb G. Salvan,b D. R. T. Zahn,b J. Park,c,d Y. Krupskaya,d V. Kataev,d R. Klingeler,c B. Büchner,d B. Mahns,d M. Knupfer,d P. Siles,d O. G. Schmidt,d A. Reis,e W. R. Thiel,e D. Breite,f B. Abel,f and B. Kersting,a,*
Affiliations : a) Universität Leipzig, D-04103 Leipzig, Germany, b) Technische Universität Chemnitz, D-09107 Chemnitz, Germany c) University of Heidelberg, D-69120 Heidelberg, Germany d) IFW Dresden, D-01171 Dresden, Germany e) TU Kaiserslautern, D-67663 Kaiserslautern, Germany f) Leibniz-Institut für Oberflächenmodifizierung e. V., D-04318 Leipzig, Germany

Resume : A new strategy for the fixation of redox-active dinickel(II) complexes with high-spin ground states to gold surfaces was developed. The complexes were fully characterized by ESI mass spectrometry, IR, and UV/vis spectroscopy, X-ray crystallography (2BPh4 and 4BPh4), cyclic voltammetry, SQUID magnetometry, and HF-ESR spectroscopy. Temperature-dependent magnetic susceptibility measurements reveal a ferromagnetic coupling J=+15.9 and +17.9 cm−1 between the two NiII ions in 2ClO4 and 4BPh4 (H=−2JS1S2). HF-ESR measurements yield a negative axial magnetic anisotropy (D<0), which implies a bistable (easy axis) magnetic ground state. The binding of the [Ni2L(dppba)]ClO4 complex to gold was ascertained by four complementary surface analytical methods: contact angle measurements, atomic-force microscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The results indicate that the complexes are attached to the Au surface through coordinative AuP bonds in a monolayer.

M.M.VII..3
16:30
Authors : Masahiro Yamashita
Affiliations : Tohoku University

Resume : Quantum spintronics will become a key technology in 21st century. We have synthesized the conducting Single-Molecule Quantum Magnets (SMM) such as [Pc2Tb]Cl0.6, whose blocking temperature is 47K. The hysteresis is observed below 10K. This SMM shows the negative magnetoresistance below 8 K by the interaction between the conducting electron and TbPc2( SMM) for the first time. As for the second strategy, we have tried to input/output one memory into/from double-decker Tb(III) SMM (Pc2Tb) by using the spin polarized STM (Scanning Tunneling Microscopy). In this research, we have observed Kondo Peak by using STS (Scanning Tunneling Spectroscopy) for the first time. We have succeeded in controlling the appearance and disappearance of Kondo Peak by the electron injection using STS, reversibly. This is considered as the first single-molecule memory device. As for the third strategy, we have made the FET (Field Effect Transistor) devices of SMMs. The Pc2Dy device shows the ambipolar (n- and p-type) behavior, while the Pc2Tb device shows the p-type behavior. As for the fourth strategy, we have made doping of Cs atoms onto Pc2Y, where Kondo peaks have not observed by coupling of radical of Pc and 6s electron of Cs atom to make a singlet pair, while other Pc2Y shows Kondo peak due to their radicals. As for the fifth strategy, the interactions among the magnetic Cr tip, TbPc2, and magnetic Co surface shows the giant magnetoresistance (GMR) with -200 %.

M.M.VII..4
 
Quantum theoretical approaches : Georgeta Salvan
17:00
Authors : Boris Le Guennic, Julie Jung, Olivier Cador, Kevin Bernot, F. Pointillart,
Affiliations : Université de Rennes 1; Université de Rennes 1; Université de Rennes 1; INSA Rennes; Université de Rennes 1

Resume : Complexes containing 4f elements are of great interest in molecular magnetism. They can give rise to Single-Molecule and Single-Ion Magnets (SMM/SIM) with easy-axis type anisotropy, high-energy barrier, and finally slow magnetic relaxation at low temperature. These features seem to originate from the strength and the geometry of the crystal field created by the ligands surrounding the lanthanide ion. So far, few general rules for building SMM have been formulated, but no fundamental magneto-structural relationship explaining the behaviour of lanthanide-based SMM has been proposed yet. To this end, ab initio calculations (CASSCF/PT2/RASSI-SO) are the most appropriate tool to get a reliable insight into the electronic structure of these compounds. Herein we report on our recent findings using such an approach. Among others, examples on [Ln(tta)3L] with Ln = Dy (III) and Yb(III), tta = 2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazole-methyl-2-pyridine are presented.

M.M.VIII..1
17:15
Authors : Mahbub Alam, Paul L Voss
Affiliations : Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia 30324-0250, USA UMI 2958 Georgia Tech-CNRS, Georgia Tech Lorraine, 2-3 Rue Marconi, 57070 Metz, France; Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia 30324-0250, USA UMI 2958 Georgia Tech-CNRS, Georgia Tech Lorraine, 2-3 Rue Marconi, 57070 Metz, France

Resume : We have simulated a graphene quantum interference transistor (QIT) whose current is switched by optical illumination of one of the interferometer arms. The interaction of the optical-frequency electromagnetic field with graphene acts to destroy the phase coherence of electrons in the interferometer and thus to switch electrical current. Graphene QIT photodetectors have the advantage of very small size, do not require p- and n-doped regions to form diode structures, and can achieve higher quantum efficiency than existing p-n junction graphene photodetectors because a higher percentage of absorbed photons contribute to the signal photocurrent. We use Schrodinger’s equation with Non Equilibrium Green’s Function (NEGF) formalism to simulate quantum transport of electron (1). The photon-atom interaction is calculated in lowest order perturbation theory and the self-consistent Born approximation has been used (2). We will discuss the potential routes to manufacturing such devices at interferometer lengths less than 100 nm (3). 1. Nanoscale device modeling: the Green’s function method, Superlattices and Microstructures, Vol. 28, No. 4, 2000 2. Nonequilibrium photocurrent modeling in resonant tunneling photodetectors, J. Appl. Phys. 91, 6273 (2002) 3. Exceptional ballistic transport in epitaxial graphene nanoribbons, arXiv:1301.5354

M.M.VIII..2
17:30
Authors : J. M. Skelton, R. Crespo-Otero, L. E. Hatcher, M. J. Bryant, P. R. Raithby, S. C. Parker and A. Walsh
Affiliations : Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK

Resume : Materials exhibiting reversible switching into long-lived metastable states, in response to external stimuli such as heat, light, or chemical vapour, can have a wide variety of applications, e.g. as sensors or electronic components. Understanding the processes which underpin this behaviour represents a theoretical challenge, but is an essential step towards being able to “design” molecular materials with optimal properties for particular applications. We are using first-principles computational modelling to study switching behaviour in a variety of molecular crystals, in order to investigate the quantum-level changes which give rise to their unique properties. This talk will present our recent work on two model systems. The first is a Ni-NO2 complex, representing a family of materials which display linkage isomerisation - a change in the binding mode of a ligand to the metal - when activated by light and, in some cases, also by heat. The second is a planar Pt complex, which undergoes dramatic, fast and reversible colour changes when exposed to water vapour and methanol. By using a variety of quantum chemistry techniques, e.g. molecular dynamics, transition-state searching and time-dependent density-functional theory (TD-DFT), we have been able to gain insight into the switching processes, and this fundamental understanding may be utilised to optimise these and similar systems, as well as to identify alternative candidate materials.

M.M.VIII..3
17:45
Authors : Karolina Z. Milowska, Jacek K. Stolarczyk,
Affiliations : 1)Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany 2)Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 Munich, Germany; 1)Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany 2)Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 Munich, Germany

Resume : Metal nanoparticles possess unique chemical, optical, electrical and magnetic properties unavailable in their bulk limit. Their novel hierarchically-ordered nanoparticles assemblies attract a lot of research activity because of wide range of potential applications. We present results of extensive and systematic studies of periodically assembled (1D, 2D & 3D) ligand-protected Au nanoparticles. Our studies are based on the ab initio calculations in the framework of the density functional theory (DFT) and provide valuable quantitative predictions that are of importance for the design of functional devices. We have performed calculations for 7 different gold clusters (Au13, Au16, Au19, Au38, Au55, Au79 and Au144) protected with different lengths of thiolate ligands (-S(CH2)nCH3, n=0,..,7). We have studied the ligand binding to the surface of Au cluster with respect to surface curvature, crystal orientation and the ligand length. Furthermore, we have calculated adsorption and binding energies as the measure of the stability of those systems. For the assemblies we have also determined the dependence of interparticle interaction potential on particle separation, which is essential for studies of self-assembly process.

M.M.VIII..4
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Molecular Self-assembly : Mario Ruben
08:30
Authors : Richard E. P. Winpenny
Affiliations : School of Chemistry and Photon Science Institute, The University of Manchester

Resume : We are learning how to link together polymetallic compounds to give complex structures and learning to address such compounds used pulsed EPR spectroscopy.1,2 During this presentation recent work will be discussed in two distinct approaches. Firstly, we will describe recent work creating new hybrid inorganic-organic rotaxanes3 (Figure 1a) and in the second approach we will discuss functionalising polymetallic rings so that they can act as ligands for other metal complexes (Figure 1b).4 Figure 1. (a) A [3]rotaxane involving two {Cr7Ni} rings; (b) six {Cr7Ni} rings attached to a {Ni12} rings forming a “ring of rings”. References: 1. F. Moro, D. Kaminski, F. Tuna, G. F. S. Whitehead, G. A. Timco, D. Collison, R. E. P. Winpenny, A. Ardavan and E. J. L. McInnes, Chem. Commun., 2014, 50, 91. 2. C. J. Wedge, R. E. George, G. A. Timco, F. Tuna, S. Rigby, E. J. L. McInnes, R. E. P. Winpenny, S. J. Blundell and A. Ardavan, Phys. Rev. Lett., 2012, 108, 107204. 3. C.- F. Lee, D. A. Leigh, R. G. Pritchard, D. Schultz, S. J. Teat, G. A. Timco and R. E. P. Winpenny, Nature, 2009, 458, 314. 4. G. F. S. Whitehead, F. Moro, G. A. Timco, W. Wernsdorfer, S. J. Teat and R. E. P. Winpenny, Angew. Chem. Int. Ed., 2013, 52, 9932.

M.M.IX..1
09:00
Authors : N. Crivillers,1,2 C. Munuera,1 M. Paradinas,1 M. Mas-Torrent,1,2 C. Simão,1,2 S. T. Bromley,3,4 C. Ocal,1 C. Rovira,1,2 J. Veciana1,2
Affiliations : 1 Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra,Spain. 2 Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) ICMAB-CSIC,Bellaterra,Spain. 3 Departament de Quıímica Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona,08028 Barcelona, Spain. 4 Institució Catalana de Recerca i Estudis Avançats (ICREA),08010 Barcelona, Spain

Resume : The work presented here is embedded in the field of Molecular Electronics[1] For the preparation of functional organic materials devoted to be integrated in devices for application in molecular electronics we employ the molecular bottom up approach. The ultimate goal of this approach is to employ functional building blocks to construct nanometer scale devices addressed to specific applications. Furthermore, for practical device implementation the immobilisation of functional molecules on suitable surfaces is also often required. One powerful and versatile strategy for the modification of surfaces at the molecular level is via the preparation of self-assembled monoalyers (SAMs). The use of SAMs as components in electronic devices has attracted great attention from researchers of different fields. In some cases the SAM is used to modulate the performance of the device but, it can also be employed as the electro-active component, i.e., the functionality of the device relies on the properties of the molecules forming the SAM. Our research is focused on the preparation of SAMs based on functional molecules that show bi-stability and hence can act as molecular switches. Magnetic and electroactive molecules have been grafted on a substrate and it has been demonstrated that can perform as robust and non-volatile molecular memory devices.[2] In addition, some of our studies rely on the use of unpaired spin-containing molecules which opens the possibility to explore the spin transport properties of these organic systems for information storage.[3] Our charge transport studies rely on the transport properties comparison between two SAMs based on the closed and open-shell forms of polychlorinated triphenylmethyl (PTM) derivatives that exhibit small differences in their molecular structure but strongly differ in their electronic configuration. [1] James R. Heath. Annu. Rev. Mater. Res. 2009, 39, 1-23. b) Special issue. Nat. Nanotechnol. 2013, 8, 377-467. [2] Claudia Simão, Marta Mas-Torrent, Núria Crivillers, Vega Lloveras, Juan Manuel Artés, Pau Gorostiza, Jaume Veciana and Concepció Rovira. Nat. Chem. 2011, 3, 359-363. [3] a) Núria Crivillers, Carmen Munuera, Marta Mas-Torrent, Claudia Simão, Stefan. T. Bromley, Carmen. Ocal, Concepció Rovira, Jaume Veciana. Adv. Mater. 2009, 21, 1177-1181. b) Núria Crivillers, Markos Paradinas, Marta Mas-Torrent, Stefan T. Bromley, Concepció Rovira, Carmen Ocal, Jaume Veciana. Chem. Commun. 2011, 47, 4664-4666.

M.M.IX..2
09:15
Authors : Danielle Laurencin, Yannick Guari, Matthieu Paillet, Sébastien Richeter
Affiliations : University Montpellier 2, Institut Charles Gerhardt, France; University Montpellier 2, Institut Charles Gerhardt, France; University Montpellier 2, Laboratoire Charles Coulomb, France; University Montpellier 2, Institut Charles Gerhardt, France.

Resume : Due to their outstanding optical, electronic and catalytic properties, much effort has been made to prepare porphyrin-based functional materials. In particular, a variety of porphyrin nanofibers, nanotubes, or nanospheres have been described. Among the different synthetic strategies used to prepare these nano-objects, self-assembly reactions between organic cations and anions have been looked into. However, in most cases, details of their structure at the molecular scale could not be derived from simple X-ray diffraction analyses, and assumptions on the arrangement of the anionic and cationic components have been made based on UV-visible spectrophotometric analyses. Here, we will describe the synthesis of a new family of porphyrin nano-rods, prepared by self-assembly between charged porphyrins (e.g. 5,10,15,20-meso-tetrakis(4-N-methylpyridinium)porphyrin) and oppositely charged bulky organic ions (e.g. tetraphenylborate). Details on the structure of these nanoobjects will be provided through an unprecedented combination of 1- and 2-dimensional solid state NMR experiments, with a particular focus on the relative arrangement of the two ions. Finally, details on their optical and sensing properties will also be presented.

M.M.IX..3
09:30
Authors : Yannick VIERO, Stéphane LENFANT, David GUERIN, Dominique VUILLAUME
Affiliations : Molecular Nanostructures & Devices Group, Institute for Electronics Microelectronics and Nanotechnology, CNRS & University of Lille, B.P. 60069, 59652, Villeneuve d’Ascq, France

Resume : Switchable molecules are of particular interest in the perspective of molecular electronics, molecular machines or biosensors. One of the main challenges remains the creation of active devices based on those molecular switches. We have previously shown that a new Azobenzene BiThiophene derivative (AzBT) was a good candidate as it was possible to monitor the conductivity of a Self-Assembled Monolayer (SAM) of those molecules upon UV/blue irradiation (365/470 nm) with high conductance ratios up to 7.10^3. We show that AzBT molecules can cap gold nanoparticles. Cycles of UV/blue irradiation produce variations of the absorbance in the ligand region, demonstrating the switching ability of AzBT-AuNPs in solution. We form Nano-Particle Self-Assembled Networks (NPSANs) and transfer them on silicon substrates with lithographed electrodes (gaps from 30 nm to 200 µm). The nanoparticles here act as a controlled template bridged by interdigitated AzBT molecules. Electrical measurements show conductance variations of NPSANs upon UV/blue irradiations. The current switches from an “on” to an “off” state, associated to a cis/trans-isomerization of the molecules. We repeatedly photoswitched the conductance with typical “on/off” ratios of 6, improving previous literature results (“on/off” ratio < 2).2 Work financially supported by EU FET project SYMONE (n° 318597) and ANR SYNAPTOR (n° 12-BS03-010). 1 Smaali et al., ACS Nano 4, 2411 (2010) 2 Van der Molen et al., Nano Letters 9, 76 (2009)

M.M.IX..4
09:45 Closing remarks Symposium M - Poster Prizes (Mario Ruben)    
12:00 LUNCH    
16:00 PLENARY SESSION    

No abstract for this day

No abstract for this day