Orbital angular momentum driven intrinsic spin Hall effect

TL;DR

This paper introduces a new intrinsic spin Hall effect mechanism driven by local orbital angular momentum, linking orbital and spin phenomena through atomic spin-orbit coupling, with predictions matching experimental observations.

Contribution

It proposes a novel mechanism where orbital angular momentum induces an orbital Hall effect that leads to the spin Hall effect, highlighting the role of atomic spin-orbit coupling.

Findings

Spin Hall conductivity is comparable to experimental values in heavy metals.

Predicts sign change of spin Hall conductivity with spin-orbit polarization.

Correlates spin Hall conductivity with Rashba spin splitting at surfaces.

Abstract

We propose a mechanism of intrinsic spin Hall effect (SHE). In this mechanism, local orbital angular momentum (OAM) induces electron position shift and couples with the bias electric field to generate orbital Hall effect (OHE). SHE then emerges as a concomitant effect of OHE through the atomic spin-orbit coupling. Spin Hall conductivity due to this mechanism is estimated to be comparable to experimental values for heavy metals. This mechanism predicts the sign change of the spin Hall conductivity as the spin-orbit polarization changes its sign, and also correlation between the spin Hall conductivity and the splitting of the Rashba-type spin splitting at surfaces.