Special Atomic, Molecular, and Optical Physics Seminar: Ebrahim Sajadi, University of British Columia, “Quantum transport in 2D Topological Insulators”

Topological insulators (TI) have been the subject of intense theoretical and experimental investigation due to their distinct electronic properties compared to conventional electronic systems. In my talk, I will discuss electronic properties of two topological insulators, InAs/GaSb double quantum wells and monolayer WTe2, through transport measurements at low temperatures.
Using double gate geometry, InAs/GaSb quantum wells can be tuned between topological and trivial states. Previous works have reported the existence of robust helical edge conduction in the inverted regime. Here, we found an enhanced edge conduction in the trivial state with superficial similarity to the observed edge conduction in those reports. However, using various transport techniques and sample geometries, the edge conduction in our samples was found to have a non-helical origin.
In the second part of my talk, I will discuss another 2D topological insulator, monolayer WTe2. Here, I will show that monolayer WTe2, already known to be a 2D TI, becomes a superconductor by mild electrostatic doping, at temperatures below 1K. The 2D TI-superconductor transition can be easily driven by applying a small gate voltage.
Host: Jack Harris