Electrically modulated SQUID with single Josephson junction coupled by a time-reversal breaking Weyl semimetal thin film

TL;DR

This paper proposes an electrically modulated SQUID using a single Josephson junction coupled with a Weyl semimetal thin film, where the interference is controlled by an electric field, offering a new way to identify magnetic Weyl semimetals and potential quantum computing applications.

Contribution

It introduces a novel electrically controlled SQUID with a single Josephson junction and Weyl semimetal, highlighting the role of surface and bulk states in current modulation.

Findings

Fermi arc surface states mediate Josephson current at low Fermi energy.

The ground-state phase difference  is proportional to electric field and junction area.

Interference between surface and bulk channels enables electric modulation of the SQUID.

Abstract

Usually, the superconducting quantum interference device (SQUID) consists of two Josephson junctions and the interference therein is modulated by a magnetic flux. In this work, we propose an electrically modulated SQUID consisting of single Josephson junction coupled by a time-reversal breaking Weyl semimetal thin film. For a low Fermi energy, the Josephson current is only mediated by Fermi arc surface states, and has an arbitrary ground-state phase difference \phi0 which is directly proportional to the product of the transverse electric field and the cross section area of the junction.For a suitable Fermi energy, the bulk states make comparable contributions to the Josephson current with the current-phase relation of a 0-junction. The interference between the surface channel and the bulk channel results in an electrically modulated SQUID with single Josephson junction, which provides an experimental proposal to identify magnetic Weyl semimetals and may have potential applications in superconducting quantum computation.