Spin Orbit coupling and Anomalous Josephson effect in Nanowires

TL;DR

This paper investigates the anomalous Josephson effect in superconductor-semiconducting nanowire heterostructures with spin-orbit coupling and magnetic fields, highlighting conditions that enhance the supercurrent without phase difference.

Contribution

It introduces a multi-band model to analyze the anomalous Josephson effect and identifies geometrical and symmetry conditions that enhance this phenomenon.

Findings

Anomalous supercurrent occurs without phase difference.

Proximity to a band opening enhances the effect.

Symmetry conditions are crucial for finite supercurrent.

Abstract

A superconductor-semiconducting nanowire-superconductor heterostructure in the presence of spin orbit coupling and magnetic field can support a supercurrent even in the absence of phase difference between the superconducting electrodes. We investigate this phenomenon, the anomalous Josephson effect, employing a model capable of describing many bands in the normal region. We discuss geometrical and symmetry conditions required to have finite anomalous supercurrent and in particular we show that this phenomenon is enhanced when the Fermi level is located close to a band opening in the normal region.