The Waterloo Institute for Nanotechnology (WIN) presents a seminar by Professor Hao Zeng, from the University at Buffalo, the State University of New York Buffalo.
Chalcogenide Compounds- A Magical Class of Functional Materials
Abstract
Recent “hot topics” in condensed matter physics, ranging from thin film photovoltaics and phase change memory to topological insulators and two-dimensional semiconductors, share one thing in common: they are all based on chalcogenide materials. In this talk, Professor Zeng will discuss his recent research efforts on two classes of such materials: twodimensional (2D) transition-metal dichalcogenides (TMDCs) and chalcogenide perovskites.
TMDCs have been intensively studied in the past few years. A monolayer TMDC with broken inversion symmetry possesses two degenerate valleys that can be selectively excited by circularly polarized light. The valley degeneracy can be broken by an external magnetic field, leading to valley Zeeman splitting. The valley splitting can be enhanced by more than an order of magnitude, by exploiting the interfacial exchange field from a ferromagnetic substrate. This approach opens up new possibilities for valley control for valleytronics applications.