Static polarizability of two-dimensional hole gases

TL;DR

This paper calculates the static density response of a 2D hole gas considering complex valence band structures, revealing unique features due to HH-LH splitting and mixing, impacting dielectric properties.

Contribution

It provides a detailed calculation of the Lindhard response function for 2D hole gases using Luttinger's k·p model, highlighting effects absent in electron gases.

Findings

Lindhard function shows unique features due to HH-LH splitting.

HH-LH mixing affects the dielectric response.

Results have implications for understanding 2D hole systems.

Abstract

We have calculated the density-density (Lindhard) response function of a homogeneous two-dimensional (2D) hole gas in the static (omega=0) limit. The bulk valence-band structure comprising heavy-hole (HH) and light-hole (LH) states is modeled using Luttinger's kdotp approach within the axial approximation. We elucidate how, in contrast to the case of conduction electrons, the Lindhard function of 2D holes exhibits unique features associated with (i) the confinement-induced HH-LH energy splitting and (ii) the HH-LH mixing arising from the charge carriers' in-plane motion. Implications for the dielectric response and related physical observables are discussed.