报告题目：Spin-valleytronics in the moiré pattern of van der Waals heterostructures

报 告 人：Wang YAO，Department of Physics, University of Hong Kong

报告时间：2017-06-08 16:00

报告地点：郑裕彤讲堂

报告摘要：In monolayer transition metal dichalcogenides (TMDs), a newly emerged class of 2D semiconductors, the low energy carriers are described by massive Dirac cones located at K and -K corners (valleys) of the Hexagonal Brillouin zone. These massive Dirac Fermions have interesting phenomena associated with their valley index, including the valley optical transition selection rules and valley Hall effects, which enable the use of both valley and spin (via spin-valley coupling) as information carriers in future electronics. Van der Waals stacking of 2D semiconductors into heterostructures further provides a powerful approach towards designer quantum materials that extend the exotic properties of the building blocks. As a generic aspect of these vdW heterostructures, the inevitable lattice mismatch always leads to the formation of moiré pattern (i.e. periodic variation of local atomic registries). I will show that the vdW moiré can endow heterostructures unprecedented properties, including electrically switchable lateral superstructures of topological Insulators, nano-patterned spin optics, and spin-orbit coupled excitonic superlattices.