"Edge transport in the trivial phase of InAs/GaSb"

Fabrizio Nichele: Henri J Suominen , Morten Kjaergaard , Charles M Marcus , Ebrahim Sajadi , Joshua A Folk , Fanming Qu , Arjan J A Beukman , Folkert K de Vries , Jasper van Veen4 , Stevan Ndj-Perge , Leo P Kouwenhoven , Binh-Minh Nguyen , Andrey A Kiselev ,Wei Yi , Marko Sokolich , Michael J Manfra, Eric M Spanton and Kathryn A Moler; New Journal of Physics, 07/28/16.

Additional Authors: Henri J Suominen , Morten Kjaergaard , Charles M Marcus , Ebrahim Sajadi , Joshua A Folk , Fanming Qu , Arjan J A Beukman , Folkert K de Vries , Jasper van Veen4 , Stevan Ndj-Perge , Leo P Kouwenhoven , Binh-Minh Nguyen , Andrey A Kiselev ,Wei Yi , Marko Sokolich , Michael J Manfra, Eric M Spanton and Kathryn A Moler

Abstract:

We present transport and scanning SQUID measurements on InAs/GaSb double quantum wells, a system predicted to be a two-dimensional topological insulator. Top and back gates allow independent control of density and band offset, allowing tuning from the trivial to the topological regime. In the trivial regime, bulk conductivity is quenched but transport persists along the edges, superficially resembling the predicted helical edge-channels in the topological regime. We characterize edge conduction in the trivial regime in a wide variety of sample geometries and measurement configurations, as a function of temperature, magnetic field, and edge length. Despite similarities to studies claiming measurements of helical edge channels, our characterization points to a nontopological origin for these observations.