报告人：Yang Zhang (UTK Physics)

时间地点：2023年6月13日周二下午4:00，理科楼B315

报告摘要：Transition metal dichalcogenide (TMD) based moiré materials have been shown to host various correlated electronic phenomena including Mott insulating states and fractional filling charge orders, quantum spin Hall effects, and (fractional) quantum anomalous Hall. To describe the low-energy states of long-wavelength moiré superlattice, we introduced the concept of moiré quantum chemistry and developed the moiré density functional theory to study the filling-dependent insulating state and emergent magnetic properties. In twisted bilayer TMD, we proposed the electrically tunable charge order and interaction-induced Mott ferroelectricity and pseudogap metal from spin polarons. In AB hetorobilayers MoTe2/WSe2, we developed the theory of moiré Chern bands. Valley contrasting Chern bands with non-trivial spin texture are formed from interlayer hybridization between moiré bands of nominally opposite spins. I will also discuss the fractional quantum anomalous Hall effect in twisted homobilayer. This series of works reveal the rich physics of semiconductor moiré superlattices as manifested in a variety of correlated and topological states.

报告人简介：Yang is an assistant professor in physics at the University of Tennessee, Knoxville. He received his BE degree from Tsinghua University and Ph.D. in Physics from Max Planck Institute Dresden, then he worked as a postdoc at MIT. His research interest lies in understanding the topological states, quantum transport, and light-matter interaction in quantum materials. Yang has received several awards, including two overall Winner Awards in the World Supercomputing Contest, the Tschirnhaus Medal from the Leibniz Association, and the Otto-Hahn Medal of the Max Planck Society.