Plasmon spectrum of two-dimensional electron systems with Rashba spin-orbit interaction

TL;DR

This paper investigates how Rashba spin-orbit interaction influences the plasmon spectrum in two-dimensional electron systems, revealing frequency shifts, oscillations, and damping effects in single and double quantum wells.

Contribution

It provides a detailed analysis of the impact of Rashba spin-orbit interaction on plasmon modes in 2DEGs within quantum wells, highlighting new effects on frequency and damping.

Findings

Rashba spin-orbit interaction causes overall frequency lowering of plasmons.

Spin-split bands induce weak frequency oscillations in the plasmon spectrum.

Enhanced Landau damping occurs due to inter-branch single-particle excitations.

Abstract

The dielectric function and plasmon modes of a two-dimensional electron gas (2DEG) are studied in single- and double-quantum-well structures with Rashba spin-orbit interaction (RSOI) in the framework of the random-phase approximation. The RSOI splits each parabolic energy subband of a 2DEG into two nonparabolic spin branches and affects the electronic many-body correlation and dielectric properties of the 2DEG. The influence of the RSOI on the 2DEG plasmon spectrum in single quantum wells appear mainly in three ways: 1) an overall frequency lowering due to the energy band deformation; 2) a weak frequency oscillation stemming from the spin-split energy band; and 3)an enhancement of the Landau damping as a result of the emerging of the inter-branch single-particle-excitation spectrum. In double quantum wells, the above effects are enhanced for the optic plasmon mode but diminished for the acoustic one.