Spin-density induced by electromagnetic wave in two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit couplings

TL;DR

This paper investigates how microwave excitation induces out-of-plane spin polarization in a 2D electron gas with combined Rashba and Dresselhaus spin-orbit couplings, highlighting the dominant spin-orbit contribution in clean systems.

Contribution

It extends previous work by analyzing the combined effects of Rashba and Dresselhaus couplings on microwave-induced spin polarization in 2DEG systems.

Findings

Out-of-plane spin polarization is generated by microwave fields.

Spin-orbit contribution to magnetization exceeds Zeeman effect in clean systems.

Effect disappears when Rashba and Dresselhaus couplings are equal.

Abstract

We consider the magnetic response of a two-dimensional electron gas (2DEG) with both Rashba and Dresselhaus spin-orbit coupling to a microwave excitation. We generalize the results of [A. Shnirman and I. Martin, Europhys. Lett. 78, 27001 (2007).], where pure Rashba coupling was studied. We observe that the microwave with the in-plane electric field and the out-of-plane magnetic field creates an out-of-plane spin polarization. The effect is more prominent in clean systems with resolved spin-orbit-split subbands. Considered as response to the microwave magnetic field, the spin-orbit contribution to the magnetization far exceeds the usual Zeeman contribution in the clean limit. The effect vanishes when the Rashba and the Dresselhaus couplings have equal strength.