Rashba proximity states in superconducting tunnel junctions

TL;DR

This paper introduces a novel superconducting proximity effect involving spin-split Cooper pairs in tunnel junctions, demonstrating how supercurrents can be controlled via spin-orbit coupling manipulated electrically and mechanically.

Contribution

It reveals a new type of proximity effect with spin-split Cooper pairs and shows how to control supercurrents through spin-orbit coupling in quantum dot-based junctions.

Findings

Supercurrent can be manipulated by spin-orbit coupling.

Spin states of Cooper pairs are split into singlet and triplet components.

Electrical and mechanical control of supercurrent is feasible.

Abstract

We consider a new kind of superconducting proximity effect created by the tunneling of "spin split" Cooper pairs between two conventional superconductors connected by a normal conductor containing a quantum dot. The difference compared to the usual superconducting proximity effect is that the spin states of the tunneling Cooper pairs are split into singlet and triplet components by the electron spin-orbit coupling, which is assumed to be active in the normal conductor only. We demonstrate that the supercurrent carried by the spin-split Cooper pairs can be manipulated both mechanically and electrically for strengths of the spin-orbit coupling that can realistically be achieved by electrostatic gates.