Plasmons in spin-orbit coupled two-dimensional hole gas systems

TL;DR

This paper investigates the anisotropic plasmon behavior in spin-orbit coupled two-dimensional hole gases in GaAs and InAs quantum wells, highlighting how electric fields influence plasmon lifetimes for potential transistor applications.

Contribution

It extends the Luttinger model to include the lowest subbands and inversion asymmetries, revealing anisotropic plasmon dispersion and controllable plasmon lifetimes in hole gases.

Findings

Plasmon dispersion is highly anisotropic in these systems.

Landau damping suppresses plasmons in certain orientations in GaAs.

Electric fields can tune plasmon lifetimes in InAs via Rashba effects.

Abstract

We study the dynamical dielectric function of a two-dimensional hole gas, exemplified on [001]-GaAs and InAs quantum wells, within the Luttinger model extended to the two lowest subbands including bulk and structure inversion asymmetric terms. The plasmon dispersion shows a pronounced anisotropy for GaAs- and InAs-based systems. In GaAs this leads to a suppression of plasmons due to Landau damping in some orientations. Due to the large Rashba contribution in InAs, the lifetime of plasmons can be controlled by changing the electric field. This effect is potentially useful in plasmon field effect transistors as previously proposed for electron gases.