Edge channel transport in InAs/GaSb combined quantum wells
Event details
| Date | 20.02.2015 |
| Hour | 14:15 |
| Speaker | Prof. Werner Wegscheider, Laboratory for Solid State Physics, Physics Department, ETH Zürich |
| Location | |
| Category | Conferences - Seminars |
Adjacent InAs and GaSb layers, which are characterized by a broken-gap (type II) band alignment at the interface, so-called combined quantum wells (CQWs), have exceptional properties. As a consequence of the spatial separation of electron and hole wave functions, the resulting state of matter becomes electric-field tunable. In particular, for maximum overlap of electron and hole wave-functions a hybridization gap opens and with the Fermi level in this gap the system constitutes a 2D topological insulator (TI). In this talk I will present growth investigations of such InAs/GaSb heterostructures and correlate these with the transport properties of the 2D TI system. In gate-tunable structures we observe the crossover from electron to hole transport. At the charge neutrality point a giant nonlocal response, indicative for the presence of helical quantum Hall edge channels, is observed under strong perpendicular magnetic fields. In hybrid structures, made from InAs/GaSb CQWs and superconductors, superconducting transport is observed. Using superconducting quantum interference (SQI), we were able to demonstrate tuning between edge-dominated and bulk dominated transport regimes as a function of electrostatic gating.
Bio: Werner Wegscheider has been Professor in the Laboratory for Solid State Physics at ETH Zurich since February 2009.
Bio: Werner Wegscheider has been Professor in the Laboratory for Solid State Physics at ETH Zurich since February 2009.
Practical information
- Informed public
- Free
Organizer
- ICMP (Arnaud Magrez and Raphaël Butté)
Contact
- Arnaud Magrez ([email protected])