Swapping of spin currents: interchanging spin and flow directions

TL;DR

This paper introduces a novel spin transport phenomenon called swapping, where spin and flow directions interchange due to spin-orbit interaction, potentially leading to unique spin accumulation effects.

Contribution

It uncovers a new spin current transformation mechanism caused by spin-orbit interaction, distinct from skew scattering, and applicable within the first Born approximation.

Findings

Swapping effect exists due to spin-orbit interaction in scattering.

Swapping leads to spin accumulation with polarization perpendicular to the surface.

The effect is more robust than skew scattering, occurring in the first Born approximation.

Abstract

We introduce a previously unknown spin-related transport phenomenon, consisting in a transformation (swapping) of spin currents, in which the spin direction and the direction of flow are interchanged. Swapping is due to the spin-orbit interaction in scattering. It originates from the correlation between the spin rotation and the scattering angle. This effect is more robust than the skew scattering, since it exists already in the first Born approximation. Swapping may lead to the spin accumulation with spin polarization perpendicular to the surface, unlike what happens in the spin Hall effect.