Intrinsic Spin and Orbital-Angular-Momentum Hall Effect

TL;DR

This paper redefines intrinsic and extrinsic transport coefficients, demonstrating that the intrinsic spin Hall effect is not a transport phenomenon and always involves an orbital-angular-momentum counterpart, challenging previous interpretations.

Contribution

It introduces a generalized framework for transport coefficients and clarifies the nature of the intrinsic spin Hall effect as non-transport, with implications for spintronics.

Findings

Intrinsic transport coefficients depend only on local electronic structure.

Intrinsic spin Hall current is always accompanied by an opposite orbital-angular-momentum current.

Intrinsic spin Hall effect does not cause edge spin accumulation.

Abstract

A generalized definition of intrinsic and extrinsic transport coefficients is introduced. We show that transport coefficients from the intrinsic origin are solely determined by local electronic structure, and thus the intrinsic spin Hall effect is not a transport phenomenon. The intrinsic spin Hall current is always accompanied by an equal but opposite intrinsic orbital-angular-momentum Hall current. We prove that the intrinsic spin Hall effect does not induce a spin accumulation at the edge of the sample or near the interface.