Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells

TL;DR

This study demonstrates continuous electric and magnetic field tuning between trivial and topological phases in InAs/GaSb double quantum wells, revealing a rich phase diagram and providing a method to distinguish topological states.

Contribution

It experimentally explores the trivial-topological phase diagram in InAs/GaSb DQWs using dual-gating and magnetic fields, a previously uncharted territory.

Findings

Continuous electric tuning between phases achieved

Magnetic field shifts bands to differentiate topological states

Rich phase diagram experimentally mapped

Abstract

Among the theoretically predicted two-dimensional topological insulators, InAs/GaSb double quantum wells (DQWs) have a unique double-layered structure with electron and hole gases separated in two layers, which enables tuning of the band alignment via electric and magnetic fields. However, the rich trivial-topological phase diagram has yet to be experimentally explored. We present an in situ and continuous tuning between the trivial and topological insulating phases in InAs/GaSb DQWs through electrical dual-gating. Furthermore, we show that an in-plane magnetic field shifts the electron and hole bands relatively to each other in momentum space, functioning as a powerful tool to discriminate between the topologically distinct states.