Spin magnetotransport in two-dimensional hole systems

TL;DR

This paper investigates how a weak magnetic field influences spin currents in two-dimensional hole systems within asymmetric quantum wells, revealing non-monotonic behavior and enhancement of spin-Hall conductivity due to combined spin-orbit and Zeeman effects.

Contribution

It provides a theoretical analysis of spin magnetotransport in 2D hole systems, accounting for disorder, spin-orbit, and Zeeman interactions, highlighting magnetic field effects on spin currents and conductivity.

Findings

Transverse and diagonal spin currents are excited by electric fields.

Diagonal spin current changes sign at finite magnetic field H.

Spin-Hall conductivity is significantly enhanced and non-monotonically dependent on H.

Abstract

Spin current of two-dimensional holes occupying the ground-state subband in an asymmetric quantum well and interacting with static disorder potential is calculated in the presence of a weak magnetic field H perpendicular to the well plane. Both spin-orbit coupling and Zeeman coupling are taken into account. It is shown that the applied electric field excites both the transverse (spin-Hall) and diagonal spin currents, the latter changes its sign at a finite H and becomes greater than the spin-Hall current as H increases. The effective spin-Hall conductivity introduced to describe the spin response in Hall bars is considerably enhanced by the magnetic field in the case of weak disorder and demonstrates a non-monotonic dependence on H.