Spin-density induced by electromagnetic wave in two-dimensional electron gas

TL;DR

This paper investigates how electromagnetic waves induce spin polarization in a two-dimensional electron gas with spin-orbit interaction, highlighting the conditions for maximum effect and its relation to the spin-Hall effect.

Contribution

It reveals the mechanism of electromagnetic wave-induced spin polarization in 2DEG and its dependence on system purity and wave frequency, connecting it to the spin-Hall effect.

Findings

Transverse electric field induces perpendicular spin polarization.

Maximum effect occurs when wave frequency matches spin-orbit subband splitting.

Clean systems with resolved subbands show prominent spin response.

Abstract

We consider the magnetic response of a two-dimensional electron gas (2DEG) with a spin-orbit interaction to a long-wave-length electromagnetic excitation. We observe that the transverse electric field creates spin polarization perpendicular to the 2DEG plane. The effect is more prominent in clean systems with resolved spin-orbit-split subbands, and reaches maximum when the frequency of the wave matches the subband splitting at the Fermi momentum. The relation of this effect to the spin-Hall effect is discussed.