Plenary session

Imaging the Properties of Atoms and Fields down to the Picometer Scale inside Materials and Devices

David A Muller
School of Applied Physics, Cornell University, USA; David.A.Muller@cornell.edu

With recent advances in detector technology and ptychographic phase-retrieval algorithms to unscramble multiple scattering, the resolution of the electron microscope is now limited only by the dose applied to the sample, and thermal vibrations of the atoms themselves.  At high doses, these approaches have allowed us to image the detailed vibrational envelopes of individual atom columns as well as locating individual interstitial atoms.  The three-dimensional nature of the reconstruction means surface relaxations can be distinguished from the bulk structure, and atomic-scale interface roughness and step edges inside devices can be resolved – including gate-all-around transistors and Josephson junctions. Even the location of all atoms in thin amorphous films now seems within reach. The reduced sensitivity to chromatic aberrations also makes these ptychographic-like approaches of interest for thick biological or polymer samples or operando liquid-cell experiments, where we have been able to demonstrate a fivefold improvement in dose efficiency over conventional cryo-EM.