Spin Current in p-wave Superconducting Rings

TL;DR

This paper derives a formula for spin current in mesoscopic p-wave superconducting rings, showing how spin flow depends on the topological configuration of the spin state vector, with potential for circulating spin currents at zero magnetic field.

Contribution

It introduces a theoretical formula for spin current in p-wave superconductors based on mean-field theory, highlighting the role of topological numbers in spin flow direction.

Findings

Spin current depends on the topological configuration of the spin state vector.

Circulating spin currents can exist at zero magnetic field in p-wave rings.

The direction of spin current is determined by topological numbers.

Abstract

A formula of the spin current in mesoscopic superconductors is derived from the mean-field theory of superconductivity. The spin flow is generated by the spatial fluctuations of $\vec{d}$ which represents a spin state of spin-triplet superconductors. We discuss a possibility of the circulating spin current in isolated p-wave superconducting rings at the zero magnetic field. The direction of the spin current depends on topological numbers which characterize the spatial configuration of $\vec{d}$ on the ring.