Density-functional-theory-based calculations using high-performance computers have made enormous strides in describing the atomic-scale properties of complex materials and structures. In parallel, aberration-corrected scanning transmission electron microscopy (STEM) has reached extraordinary levels of spatial and energy resolution, in both imaging and electron-energy-loss spectroscopy (EELS). Recently, the advent of advanced monochromators has led to very high energy resolution in EELS, enabling atomic-resolution vibrational spectroscopy. The combination of theory and microscopy provides an unparalleled probe to unravel atomic-scale processes and probe emergent properties in nanostructures. This talk will describe examples of resolving the identity of novel structures fabricated and imaged by a STEM, imaging electron distributions and unraveling unexpected findings, a number of “firsts” in space- and momentum-resolved vibrational EELS, including atom-by-atom spectroscopy with chemical bond sensitivity, and the first application of vibrational EELS to resolve a long-standing problem in nanofluidics. Examples of theory going beyond the reach of experiments further solidifies its role as a partner in the spectacular enterprise of electron microscopy and spectroscopy.
Pantelides received a PhD in Physics from the University of Illinois in Urbana-Champaign in 1973. After 20 years at the IBM Thomas J. Watson Research Center in New York, where he carried out research in semiconductors and served as manager, senior manager, and program director, he joined the faculty at Vanderbilt University as the first McMinn Professor of Physics. For 25 years he was a Distinguished Visiting Scientist at Oak Ridge National Laboratory where he maintained a group and worked jointly with microscopists. He is currently University Distinguished Professor of Physics and Engineering at Vanderbilt and Distinguished Visiting Professor of Physics at the University of the Chinese Academy of Sciences in Beijing, China. His research focuses on theory in conjunction with experimental data on structural, electronic, magnetic, optical, and chemical properties of complex nanostructures.