Local Control of Supercurrent Density in Epitaxial Planar Josephson Junctions

TL;DR

This paper demonstrates local electrostatic control of current distribution in epitaxial Al-InAs Josephson junctions using mini-gates, enabling tailored superconducting interference devices and improved current uniformity.

Contribution

It introduces a method to locally manipulate current profiles in Josephson junctions with mini-gates, enhancing device functionality and uniformity.

Findings

Local control of current distribution achieved with mini-gates.

Edge conduction can be eliminated to improve uniformity.

Junction width and current profile are electrostatically tunable.

Abstract

The critical current response to an applied out-of-plane magnetic field in a Josephson junction provides insight into the uniformity of its current distribution. In Josephson junctions with semiconducting weak links, the carrier density and, therefore the overall current distribution could be modified electrostatically via metallic gates. Here, we show local control of the current distribution in an epitaxial Al-InAs Josephson junction equipped with five mini-gates. We demonstrate that not only can the junction width be electrostatically defined but also we can locally adjust the current profile to form superconducting quantum interference devices. Our studies show enhanced edge conduction in such long junctions, which can be eliminated by mini-gates to create a uniform current distribution.