Building the future of atom-by-atom materials characterization with electron ptychography
Electron microscopy and atomic-scale materials characterization are undergoing a revolution fueled by the new capabilities of electron ptychography, which is setting records for spatial resolution down to 20 picometers. In this talk, I will discuss how my group is developing atomically precise methods to characterize materials using electron ptychography, and the new science we are accessing using these new capabilities. These projects span from understanding structural transformation in 2D moiré materials to visualizing the 3D stacking of 2D covalent organic frameworks. In addition, I will discuss how we are making cutting-edge techniques of advanced electron microscopy more accessible by using ptychography to achieve 0.44 angstrom spatial resolution in a conventional scanning transmission electron microscope, nearly quadrupling its intrinsic resolution. Our work also indicates new frontiers to advance electron ptychography by expanding the types of electron microscopes and optical conditions that are compatible with sub-angstrom materials characterization; this work including surprising approaches that use aberrations, long an enemy of electron microscopy, to improve ptychography. Most importantly, we demonstrate that expensive aberration correctors are no longer required to achieve atom-by-atom imaging, a significant step towards democratizing access to high-end electron microscopy.
