Abstract
The layered van der Waals material WTe2 has recently attracted interested for being a topological semimetal, with type 2 Weyl points and extraordinary magnetoresistance at low temperatures. When thinned down to a monolayer we find that WTe2 exhibits unusual properties, including gapless edge states. The properties of the edge states are consistent with their being the helical boundary modes of a two-dimensional topological (quantum spin Hall) insulator. The insulating state that develops in the sample interior is quite peculiar and may require electron-hole correlations to explain. Indications of several phase transitions are seen as a function of gate voltage and temperature, and further phenomena appear on going to two and more layers.
Coffee and tea will be served 20 minutes prior to the seminar.
Anyone interested is welcome to attend.