Local Control of Supercurrent Density in Epitaxial Planar Josephson Junctions

Nano Lett. 2021 Oct 13;21(19):8274-8280. doi: 10.1021/acs.nanolett.1c02771. Epub 2021 Sep 27.

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, can 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 minigates. We demonstrate that not only can the junction width be electrostatically defined but also the current profile can be locally adjusted to form superconducting quantum interference devices. Our studies show enhanced edge conduction in such long junctions, which can be eliminated by minigates to create a uniform current distribution.

Keywords: Josephson junction; band-bending effects; electrostatic gates; supercurrent distribution.