Edge-mode Superconductivity in a Two Dimensional Topological Insulator

TL;DR

This paper demonstrates gate-tunable superconductivity in the edge modes of a 2D topological insulator, InAs/GaSb quantum wells, paving the way for studying Majorana modes and non-Abelian statistics.

Contribution

It reports the induction of superconductivity into edge modes of InAs/GaSb quantum wells and shows gate control between edge and bulk regimes, highlighting a robust platform for Majorana research.

Findings

Superconductivity is induced in InAs/GaSb edge modes.

Gate-tuning controls the transition between edge and bulk superconducting regimes.

High bulk resistivity correlates with the topological phase.

Abstract

Topological superconductivity is an exotic state of matter that supports Majorana zero-modes, which are surface modes in 3D, edge modes in 2D or localized end states in 1D. In the case of complete localization these Majorana modes obey non-Abelian exchange statistics making them interesting building blocks for topological quantum computing. Here we report superconductivity induced into the edge modes of semiconducting InAs/GaSb quantum wells, a two-dimensional topological insulator. Using superconducting quantum interference, we demonstrate gate-tuning between edge-dominated and bulk-dominated regimes of superconducting transport. The edge-dominated regime arises only under conditions of high-bulk resistivity, which we associate with the 2D topological phase. These experiments establish InAs/GaSb as a robust platform for further confinement of Majoranas into localized states enabling future investigations of non-Abelian statistics.