Spin Currents Induced by Nonuniform Rashba-Type Spin-Orbit Field

TL;DR

This paper investigates how nonuniform Rashba-type spin-orbit fields induce spin currents and relaxation torques in metals, revealing control mechanisms for spin-sink and source effects through RSOF design.

Contribution

It demonstrates that nonuniform RSOF can generate spin currents and relaxation torques without external fields, highlighting a new way to control spin dynamics in materials.

Findings

Spin relaxation torque arises from nonuniform RSOF.

Spin current is proportional to the vector chirality of RSOF.

External fields couple with RSOF to produce relaxation torque.

Abstract

We study the spin relaxation torque in nonmagnetic or ferromagnetic metals with nonuniform spin-orbit coupling within the Keldysh Green's function formalism. In non-magnet, the relaxation torque is shown to arise when the spin-orbit coupling is not uniform. In the absence of an external field, the spin current induced by the relaxation torque is proportional to the vector chirality of Rashba-type spin-orbit field (RSOF). In the presence of an external field, on the other hand, spin relaxation torque arises from the coupling of the external field and vector chirality of RSOF. Our result indicates that spin-sink or source effects are controlled by designing RSOF in junctions.