Recent evidence suggests monolayer WTe2 could be an excitonic insulator. If so, carrier doping and interaction with the substrate should heavily affect the bandgap. The Bose-Einstein condensate of excitons are predicted to exhibit charge order with a characteristic momentum.
When grown on an insulator as opposed to a conductor, we have observed the formation of a significantly larger (∼ 200 meV) bandgap. This gap appears to “collapse” with electron doping. Finally, weak charge fluctuations have been observed on the monolayer surface which persist to energies inside the bandgap.
About the presenter
Liam Watson is a PhD Student at Monash University with CI Michael Fuhrer. His project aims to grown and analyse WTe2 on insulating substrates to verify if it is an excitonic insulator, as part of FLEET’s Research Theme 1, Topological Materials.