The plasma oscillations in a two-dimensional electron-hole liquid under influence Rashba spin-orbit coupling

TL;DR

This paper investigates plasma oscillations in a 2D electron-hole liquid influenced by Rashba spin-orbit coupling, deriving dispersion relations for optical and acoustical plasmon modes under low Landau level filling.

Contribution

It provides the first analysis of plasma oscillations considering Rashba spin-orbit effects in a 2D electron-hole system at low Landau level filling.

Findings

Acoustical plasmon exhibits linear dispersion at small wave vectors.

Optical plasmon shows quadratic dispersion at long wavelengths.

Both plasmon modes saturate at higher wave vectors.

Abstract

The plasma oscillations of the two-dimensional electron-hole system in the presence of a Rashba spin-orbit coupling are studied. Only the intra-Landau level excitations are taken into account when the electrons and holes are situated on their lowest Landau levels, the filling factor $v^{2}$ being less than 1. The ground state of the two-dimensional electron-hole system is supposed to be the electron-hole liquid. The dispersion relations for the optical and acoustical plasmon modes were obtained. The acoustical plasmon branch has a linear dispersion law in the range of small wave vectors and monotonically increases with saturation at higher values of wave vectors. The optical plasmon branch has a quadratic dependence in the range of long wavelength and a monotonic increasing with saturation as in the case of acoustical branch.