Josephson Effect between Conventional and Rashba Superconductors

TL;DR

This paper investigates how Rashba spin-orbit coupling influences the Josephson effect between conventional and non-centrosymmetric superconductors, revealing phase shifts and implications for experimental observations.

Contribution

It introduces a decomposition of the Josephson coupling into spin-singlet-like and triplet-like parts, highlighting the impact of Rashba coupling on phase shifts.

Findings

Rashba spin-orbit coupling modifies Josephson pair tunneling.

The Josephson phase can shift by  relative to conventional expectations.

Results may explain experimental observations in specific superconductor junctions.

Abstract

We study the Josephson effect between a conventional s-wave superconductor and a non-centrosymmetric superconductor with Rashba spin-orbit coupling. Rashba spin-orbit coupling affects the Josephson pair tunneling in a characteristic way. The Josephson coupling can be decomposed into two parts, a `spin-singlet-like' and a `spin-triplet-like' component. The latter component can lead to shift of the Josephson phase by \pi relative to the former coupling. This has important implications on interference effects and may explain some recent experimental results for the Al/CePt3Si junction.