Intense terahertz laser fields on a two-dimensional hole gas with Rashba spin-orbit coupling

TL;DR

This study explores how intense terahertz laser fields affect the spin polarization and magnetic moments in a two-dimensional hole gas with Rashba spin-orbit coupling, revealing anisotropic effects and concentration-dependent behaviors.

Contribution

It provides a detailed analysis of the magnetic response of a 2D hole gas under terahertz fields using Floquet theory, highlighting differences from electron systems.

Findings

Terahertz magnetic moment can be induced at low hole concentrations.

The induced magnetic moment is anisotropic and depends on the field direction.

High hole concentration suppresses the magnetic moment due to interference effects.

Abstract

We investigate the influence on the density of states and the density of spin polarization for a two-dimensional hole gas with Rashba spin-orbit coupling under intense terahertz laser fields. Via Floquet theorem, we solve the time-dependent Schr\"{o}dinger equation and calculate these densities. It is shown that a terahertz magnetic moment can be induced for low hole concentration. Different from the electron case, the induced magnetic moment is quite anisotropic due to the anisotropic spin-orbit coupling. Both the amplitude and the direction of the magnetic moment depend on the direction of the terahertz field. We further point out that for high hole concentration, the magnetic moment becomes very small due to the interference caused by the momentum dependence of the spin-orbit coupling. This effect also appears in two-dimensional electron systems.