Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells

TL;DR

This paper demonstrates that the intrinsic spin Hall effect in HgTe/CdTe quantum wells appears only on the inverted side of a quantum phase transition, providing a way to distinguish it from extrinsic effects.

Contribution

The study reveals the dependence of the intrinsic spin Hall effect on the quantum phase transition in HgTe/CdTe quantum wells, highlighting a clear experimental signature.

Findings

Intrinsic spin Hall effect vanishes in the normal phase

Finite intrinsic spin Hall effect appears in the inverted phase

Provides a method to distinguish intrinsic from extrinsic effects

Abstract

Spin Hall effect can be induced both by the extrinsic impurity scattering and by the intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. This difference gives a direct mechanism to experimentally distinguish the intrinsic spin Hall effect from the extrinsic one.