Giant supercurrent states in a superconductor-InAs/GaSb-superconductor junction

TL;DR

This paper reports the observation of giant supercurrent states in an InAs/GaSb bilayer system with superconducting electrodes, demonstrating robust supercurrent behavior over wide temperature and magnetic field ranges, and revealing unique superconducting gap structures.

Contribution

It demonstrates the realization of giant supercurrent states in a topological InAs/GaSb quantum well system induced by proximity to superconductors, with extensive T-H parameter stability.

Findings

Supercurrent states are preserved over large temperature and magnetic field ranges.

Distinct superconducting gap structures are observed in differential resistance measurements.

Proximity-induced supercurrents in topological InAs/GaSb systems are experimentally confirmed.

Abstract

Superconductivity in topological materials has attracted a great deal of interest in both electron physics and material sciences since the theoretical predictions that Majorana fermions can be realized in topological superconductors [1-4]. Topological superconductivity could be realized in a type II, band-inverted, InAs/GaSb quantum well if it is in proximity to a conventional superconductor. Here we report observations of the proximity effect induced giant supercurrent states in an InAs/GaSb bilayer system that is sandwiched between two superconducting tantalum electrodes to form a superconductor-InAs/GaSb-superconductor junction. Electron transport results show that the supercurrent states can be preserved in a surprisingly large temperature-magnetic field (T-H) parameter space. In addition, the evolution of differential resistance in T and H reveals an interesting superconducting gap structure.