Sign changes and resonance of intrinsic spin Hall effect in two-dimensional hole gas

TL;DR

This paper investigates the intrinsic spin Hall effect in a two-dimensional hole gas, revealing sign changes, oscillations, and resonance phenomena influenced by magnetic fields, hole density, and spin-orbit coupling, with experimental implications.

Contribution

It demonstrates how sign changes and resonances in the intrinsic spin Hall conductance can be controlled by magnetic field, hole density, and Rashba coupling, providing new insights for experimental realization.

Findings

Sign changes in spin Hall conductance can be achieved by tuning magnetic field and Rashba coupling.

Oscillations in conductance follow Shubnikov-de Haas patterns, related to spin-orbit coupling.

Resonant conductance appears at high hole density and strong magnetic fields due to Landau level transitions.

Abstract

The intrinsic spin Hall conductance shows rich sign changes by applying a perpendicular magnetic field in a two-dimensional hole gas. Especially, a notable sign changes can be achieved by adjusting the characteristic length of the Rashba coupling and hole density at moderate magnetic fields. This sign issue may be easily realized in experiments. The oscillations of the intrinsic spin Hall conductance as a function of 1/$B$ is nothing else but Shubnikov-de Haas oscillations, and the additional beatings can be quantitatively related to the value of the spin-orbit coupling parameter. The Zeeman splitting is too small to introduce effective degeneracy between different Landau levels in a two-dimensional hole gas, and the resonant intrinsic spin Hall conductance appears in high hole density and strong magnetic field due to the transition between mostly spin-$-{1/2}$ holes and spin-3/2 holes is confirmed. Two likely ways to establish intrinsic spin Hall effect in experiments and a possible application are suggested.