Spin and charge optical conductivities in spin-orbit coupled systems

TL;DR

This paper investigates how combined Rashba and Dresselhaus spin-orbit interactions in a 2DEG influence its frequency-dependent spin and charge conductivities, revealing anisotropic spectral features and potential for optical control.

Contribution

It introduces a detailed analysis of the anisotropic optical conductivities in 2DEGs with mixed spin-orbit couplings, highlighting new spectral behaviors and methods to determine coupling strengths.

Findings

Anisotropic spectral features due to Rashba-Dresselhaus interplay

Control of optical response via external bias and light frequency

Optical probing can determine relative spin-orbit coupling strengths

Abstract

We study the frequency dependent spin- and charge- conductivity tensors of a two-dimensional electron gas (2DEG) with Rashba and Dresselhaus spin-orbit interaction. We show that the angular anisotropy of the spin-splitting energy induced by the interplay between the Rashba and Dresselhaus couplings gives rise to a characteristic spectral behavior of the spin and charge response which is significantly different from that of pure Rashba or Dresselhaus case. Such new spectral structures open the possibility for control of the optical response by applying an external bias and/or by adjusting the light frequency. In addition, it is shown that the relative strength of the spin-orbit coupling parameters can be obtained through optical probing.