title: Insights into the physical chemistry of materials from advances in HAADF-STEM.
abstract: The observation that, "New tools lead to new science"[P. S. Weiss, ACS Nano., 2012, 6(3), 1877-1879], is perhaps nowhere more evident than in scanning transmission electron microscopy (STEM). Advances in STEM have endowed this technique with several powerful and complimentary capabilities. For example, the application of high-angle annular dark-field imaging has made possible real-space imaging at sub-angstrom resolution with Z-contrast (Z = atomic number). Further advances have wrought: simultaneous real-space imaging and elemental identification by using electron energy loss spectroscopy (EELS); 3-dimensional (3D) mapping by depth sectioning; monitoring of surface diffusion by time-sequencing of images; reduced electron energy imaging for probing graphenes; etc. In this paper we review how these advances, often coupled with first-principles theory, have led to interesting and important new insights into the physical chemistry of materials. We then review in detail a few specific applications that highlight some of these STEM capabilities.
authors.affiliation: Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Sohlberg
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Pennycook
authors.forename: Wu
authors.initials: W
authors.lastname: Zhou
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Pennycook