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

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 ϕ0 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.

Chiral anomaly induced oscillations in the Josephson current in Weyl semimetals

“…The Josephson effect is one of the powerful tools to identify the superconducting pairing. Recently, the Andreev reflection 39,40 and Josephson effect [41][42][43][44][45][46] in a WSM have been theoretically investigated in several works. It has been predicted that at the interface between a timereversal breaking WSM and a conventional s-wave superconductor, the singlet pairing requires the intra-node Andreev reflection due to the spin-momentum locking of Weyl fermions [42][43][44] .…”

“…This extra momentum of the pair gives rise to an unusual oscillation in the Josephson current whose period is proportional to the distance between two paired WPs in momentum space. The effect of quan- tum interference between the bulk channel and the surface channel in Dirac semimetal based Josephson junction has also been studied recently 45 . However, the investigation in the effect of chiral anomaly on the transport in superconducting heterojunctions is still rare.…”