Screening in the two-dimensional electron gas with spin-orbit coupling

TL;DR

This paper investigates how Rashba spin-orbit coupling affects screening and collective excitations in a two-dimensional electron gas, revealing new phenomena like finite lifetimes of plasmons and phonons detectable via Raman scattering.

Contribution

It introduces a theoretical analysis of the combined effects of electron-electron interactions and spin-orbit coupling on screening and collective modes in 2D electron gases.

Findings

Spin-orbit coupling extends particle-hole excitation regions.

It induces finite lifetimes for plasmons and phonons.

Predictions are relevant for inelastic Raman scattering experiments.

Abstract

We study the interplay between electron-electron interaction and Rashba spin-orbit coupling in the two-dimensional electron gas. Using the random phase approximation we predict new screening properties of the electron gas which result in extension of the region of particle-hole excitations and in spin-orbit induced suppression of collective modes. In particular, we observe that the spin-orbit coupling gives a finite lifetime to plasmons and longitudinal optical phonons, which can be resolved in inelastic Raman scattering. We evaluate the experimentally measurable dynamic structure factor and estimate the range of parameters where the described phenomena are mostly pronounced.