Title: Excitations and dynamics in inversion symmetry-broken phases
Speaker: Jonathan E Spanier
Affiliation: Department of Materials Science & Engineering. Department of Physics. Department of Electrical & Computer Engineering. Drexel University, Philadelphia PA
Abstract: Emergent phenomena in solids, whether they involve lattice, charge, spin, orbital, or other degrees of freedom, are attractive for creating, stabilizing and/or controlling novel states of matter. New paradigms based on these phenomena are attractive candidates for capturing, converting, and carrying energy more efficiently. I will discuss two intriguing electromagnetic wave-matter interaction phenomena that can emerge in non-centrosymmetric solids. The first involves visible-light generation of two types of photovoltaic currents, one of which transforms, remarkably, a band insulator into a high-mobility conductor. In the second, we reimagine the energy landscape associated with a two-dimensional crystal defect that has traditionally been viewed as an impediment to the flow of radio-frequency microwave energy. Under special conditions a resonant behavior emerges, enabling the material to exhibit dielectric properties that exceed intrinsic limits.
Bio: Jonathan E Spanier is Professor of Materials Science & Engineering at Drexel University, where he holds affiliated faculty appointments in the Department of Physics and in the Department of Electrical & Computer Engineering. He received the PhD with Distinction from Columbia University in 2001 in applied physics and completed a two-year postdoctoral fellowship in physical chemistry at Harvard University prior to joining the Drexel faculty in 2003. He investigates the structure, physical, electronic and dielectric properties of solid-state electronic materials. He probes the interactions of light with matter, including Raman scattering revealing phase stability, the effects of symmetry and nanoscale phenomena on photovoltaic energy conversion, and electronic excitations and resonant phenomena. He also studies the solid phase epitaxy enabling formation of high-quality oxide perovskite films via atomic layer deposition. He was honored with the Presidential Early Career Award for Scientists and Engineers, the Army Research Office Young Investigator Program Award, the Distinguished Service Award from the Louis R Stokes Alliance for Minority Participation, and he was named a Louis and Bessie Stein Family Fellow. In 2016 he was elected Fellow of the American Physical Society, Division of Materials Physics.