Interlayer current near the edge of an InAs/GaSb double quantum well in proximity with a superconductor

TL;DR

This study explores how superconductivity influences charge transfer at the edge of an InAs/GaSb bilayer with a superconductor, revealing efficient coupling of electron and hole layers and magnetic field-dependent critical currents.

Contribution

It demonstrates that proximity-induced superconductivity effectively couples electron and hole layers in an InAs/GaSb quantum well at low currents.

Findings

Junction resistance is governed by interlayer charge transfer.

Superconductivity couples electron and hole layers efficiently.

Critical current varies periodically with in-plane magnetic field.

Abstract

We investigate charge transport through the junction between a niobium superconductor and the edge of a two-dimensional electron-hole bilayer, realized in an InAs/GaSb double quantum well. For the transparent interface with a superconductor, we demonstrate that the junction resistance is determined by the interlayer charge transfer near the interface. From an analysis of experimental $I-V$ curves we conclude that the proximity induced superconductivity efficiently couples electron and hole layers at low currents. The critical current demonstrates periodic dependence on the in-plane magnetic field, while it is monotonous for the field which is normal to the bilayer plane.