Supercurrent generation by spin injection in an s-wave superconductor-Rashba metal bilayer

TL;DR

This paper theoretically investigates how spin injection in a superconductor-Rashba metal bilayer induces supercurrents via spin-galvanic and inverse spin-Hall effects, highlighting potential applications in quantum devices.

Contribution

It introduces a model for supercurrent generation through spin injection in a superconductor-Rashba metal bilayer, emphasizing the role of Andreev reflection and subgap states.

Findings

Spin injection induces supercurrents via spin-galvanic and inverse spin-Hall effects.

Supercurrents relax over a length scale determined by Andreev reflection.

Potential integration into SQUIDs to mimic magnetic flux effects.

Abstract

The spin-galvanic (inverse Edelstein) and inverse spin-Hall effects are calculated for a hybrid system that combines thin superconductor and Rashba-metal layers. These effects are produced by a nonequilibrium spin polarization which is injected into the normal metal layer. This polarization gives rise to an electric potential that relaxes within some characteristic length, which is determined by Andreev reflection. Within this length the dissipative electric current of quasiparticles in the normal layer converts into the supercurrent. This process involves only subgap states and at low temperature the inelastic electron-phonon interactions are not important. It is discussed how such a hybrid system can be integrated into a SQUID where it produces an effect similar to a magnetic flux.