Carrier-density-controlled anisotropic spin susceptibility of two-dimensional hole systems

TL;DR

This study investigates the anisotropic spin susceptibility of 2D hole systems in quantum wells, revealing significant differences from electron systems and suggesting potential for magnetic switching applications.

Contribution

It provides a detailed analysis of the anisotropic and density-dependent spin response of 2D holes using the Luttinger model, highlighting novel magnetic control possibilities.

Findings

Spin susceptibility is highly anisotropic and density-dependent.

Differences from isotropic Lindhard function in 2D electron systems.

Potential for switching magnetization orientation in quantum wells.

Abstract

We have studied quantum-well-confined holes based on the Luttinger-model description for the valence band of typical semiconductor materials. Even when only the lowest quasi-two-dimensional (quasi-2D) subband is populated, the static spin susceptibility turns out to be very different from the universal isotropic Lindhard-function lineshape obtained for 2D conduction-electron systems. The strongly anisotropic and peculiarly density-dependent spin-related response of 2D holes at long wavelengths should make it possible to switch between easy-axis and easy-plane magnetization in dilute magnetic quantum wells. An effective g factor for 2D hole systems is proposed.