Two-dimensional electron gas in the regime of strong light-matter coupling: Dynamical conductivity and all-optical measurements of Rashba and Dresselhaus coupling

TL;DR

This paper develops a theoretical framework to understand how strong light-matter interactions can dynamically modify the electronic properties of 2D materials with spin-orbit coupling, enabling optical control of these interactions.

Contribution

It introduces a nonperturbative theory of dynamical conductivity in 2D electron gases with Rashba and Dresselhaus SOIs under strong electromagnetic fields, revealing new ways to probe and manipulate spin-orbit coupling.

Findings

Strong light-matter coupling alters electron dispersion qualitatively.

Optical conductivity can be tuned by electromagnetic fields.

The theory provides a method to probe and control spin-orbit interactions.

Abstract

A nonperturbative interaction of an electronic system with a laser field can substantially modify its physical properties. In particular, in two-dimensional (2D) materials with a lack of inversion symmetry, the achievement of a regime of strong light-matter coupling allows direct optical tuning of the strength of the Rashba spin-orbit interaction (SOI). Capitalizing on these results, we build a theory of the dynamical conductivity of a 2D electron gas with both Rashba and Dresselhaus SOIs coupled to an off-resonant high-frequency electromagnetic wave. We argue that strong light-matter coupling modifies qualitatively the dispersion of the electrons and can be used as a powerful tool to probe and manipulate the coupling strengths and adjust the frequency range where optical conductivity is essentially nonzero.