Anomalous Spin Polarization of GaAs Two-Dimensional Hole Systems

TL;DR

This study investigates how the shape of the confining potential influences spin subband depopulation in GaAs 2D hole systems under a parallel magnetic field, revealing unique spin polarization behavior compared to electron systems.

Contribution

It provides new insights into the spin polarization of 2D hole systems, highlighting the effects of confining potential shape and the limited role of carrier-carrier interactions.

Findings

Shape of confining potential affects depopulation magnetic field

Spin susceptibility in 2D hole systems is not significantly enhanced

Band structure and effective spin j=3/2 influence spin behavior

Abstract

We report measurements and calculations of the spin-subband depopulation, induced by a parallel magnetic field, of dilute GaAs two-dimensional (2D) hole systems. The results reveal that the shape of the confining potential dramatically affects the values of in-plane magnetic field at which the upper spin subband is depopulated. Most surprisingly, unlike 2D electron systems, the carrier-carrier interaction in 2D hole systems does not significantly enhance the spin susceptibility. We interpret our findings using a multipole expansion of the spin density matrix, and suggest that the suppression of the enhancement is related to the holes' band structure and effective spin j=3/2.