Transverse Josephson effect due to spin-orbit coupling: Generation of transverse current without time-reversal symmetry breaking

TL;DR

This paper demonstrates a novel transverse Josephson current caused by spin-orbit coupling in superconductor/normal metal/superconductor junctions, which occurs without breaking time-reversal symmetry and does not require an external magnetic field.

Contribution

It introduces a new type of transverse Josephson effect driven by spin-orbit coupling, distinct from known effects, and highlights its unique stationary nature without magnetic field application.

Findings

Transverse Josephson current arises from spin-orbit coupling in the normal metal.

The effect is specific to superconducting states and vanishes in the normal state.

The transverse current is stationary and does not require an external magnetic field.

Abstract

We investigate transverse Josephson current in superconductor/normal metal/superconductor junctions where the normal metal has Rashba type spin-orbit coupling. It is shown that trans- verse current arises from the spin-orbit coupling in the normal metal. This effect is specific to superconducting current and the transverse current vanishes in the normal state. In addition, this transverse Josephson effect is purely stationary and applied magnetic field is unnecessary to realize this effect, in contrast to the Hall effect in the normal state. We also discuss physical interpretation of this effect, comparing with the spin Hall effect.