Supercurrent Induced Charge-Spin Conversion in Spin-Split Superconductors

TL;DR

This paper demonstrates that in spin-split superconductors, supercurrent can induce a conversion between charge imbalance and long-range spin accumulation, enabling controllable charge-spin conversion via magnetic flux.

Contribution

It reveals the mutual coupling of charge, spin, energy, and spin energy modes in spin-split superconductors with supercurrent, showing a novel charge-spin conversion mechanism.

Findings

Supercurrent induces long-range spin accumulation from charge imbalance.

Charge-spin conversion is controllable by magnetic flux.

Different symmetry components of nonlocal conductance signal can detect this effect.

Abstract

We study spin-polarized quasiparticle transport in a mesoscopic superconductor with a spin- splitting field in the presence of co-flowing supercurrent. In such a system, the nonequilibrium state is characterized by charge, spin, energy and spin energy modes. Here we show that in the presence of both spin splitting and supercurrent, all these modes are mutually coupled. As a result, the supercurrent can convert charge imbalance, that in the presence of spin splitting decays on a relatively short scale, to a long-range spin accumulation decaying only via inelastic scattering. This effect enables coherent charge-spin conversion controllable by a magnetic flux, and it can be detected by studying different symmetry components of the nonlocal conductance signal.