Persistent spin current in a spin-orbit coupling/normal hybrid ring

TL;DR

This paper demonstrates the existence of a persistent spin current in a hybrid mesoscopic ring with spin-orbit interaction, which occurs without charge current and can be observed experimentally, highlighting a novel quantum spin phenomenon.

Contribution

It introduces the concept of a persistent spin current induced by spin Berry phase in a hybrid ring, distinct from charge currents in mesoscopic systems.

Findings

Persistent spin current exists without charge current.

The spin current is induced by spin Berry phase.

The phenomenon can be observed experimentally.

Abstract

We investigate the equilibrium property of a mesoscopic ring with spin orbit (SO) interaction. It is well known that for a normal mesoscopic ring threaded by a magnetic flux, the electron acquires a Berry phase that induces the persistent (charge) current. Similarly, the spin of electron acquires a spin Berry phase traversing the ring with SO interaction. It is this spin Berry phase that induces a persistent spin current. To demonstrate its existence, we calculate the persistent spin current without accompanying charge current in the normal region in a hybrid mesoscopic ring. We point out that this persistent spin current describes the real spin motion and can be observed experimentally.