Electrostatic tailoring of magnetic interference in quantum point contact ballistic Josephson junctions

TL;DR

This study demonstrates how electrostatic gating can dynamically modify the magnetic interference pattern in ballistic Josephson junctions, enabling tunable supercurrent control with potential applications in Majorana fermion research.

Contribution

It introduces a method to electrostatically tailor the magnetic interference in quantum point contact Josephson junctions, combining gating and magnetic field control.

Findings

Supercurrent interference pattern can be tuned from Fraunhofer-like to monotonic decay.

Electrostatic shrinking of the weak link alters the periodicity of the supercurrent.

Devices are promising for future studies of Majorana fermions.

Abstract

The magneto-electrostatic tailoring of the supercurrent in quantum point contact ballistic Josephson junctions is demonstrated. An etched InAs-based heterostructure is laterally contacted to superconducting niobium leads and the existence of two etched side gates permits, in combination with the application of a perpendicular magnetic field, to modify continuously the magnetic interference pattern by depleting the weak link. For wider junctions the supercurrent presents a Fraunhofer-like interference pattern with periodicity h/2e whereas by shrinking electrostatically the weak link, the periodicity evolves continuously to a monotonic decay. These devices represent novel tunable structures that might lead to the study of the elusive Majorana fermions.