PME Quantum Distinguished Colloquium Series Seminar - David Cobden

Excitonic instability in a two-dimensional semimetal

In a two-dimensional semimetal that contains separate small electron and hole pockets, electron-hole correlations can be strong and could, for example, lead to an instability of the Fermi surface towards exciton-like pairing. WTe2 appears to be such a semimetal, and both monolayer and bilayer WTe2 do show peculiar bulk electrical characteristics and a thermodynamic gap that opens at the charge-neutral point at a lower temperature. Suggestions that the charge-neutral state is a classic excitonic insulator are, however, confounded by the fact that no charge density wave is observed and by behavior away from the neutral condition which is beyond the excitonic insulator paradigm. I will describe our ongoing attempts to investigate this unusual electronic state and its relationship with the topological boundary modes, ferroelectricity, and superconductivity seen in the same material.

Zoom Link | Meeting ID: 970 4657 2235| Passcode: 513797

Host: Alexander High | ahigh@uchicago.edu