Dynamical screening function and plasmons in the wide HgTe quantum wells at high temperatures

TL;DR

This paper models the dynamical screening function and plasmon behavior in wide HgTe quantum wells at high temperatures, incorporating non-parabolic spectra and comparing with graphene screening, to inform high-frequency transport applications.

Contribution

It introduces a numerical model of the dynamical screening function in HgTe quantum wells using RPA, including non-parabolicity and temperature effects, and compares it with graphene screening.

Findings

Screening functions differ significantly from graphene at high temperatures.

Plasmon frequencies in HgTe QWs are calculated at 77K.

Temperature and wave-vector dependencies are characterized for high-frequency applications.

Abstract

Dynamical screening function of the two-dimensional electron gas in wide HgTe quantum well (QW) has been numerically modelled in this work. Calculations were provided in the Random Phase Approximation (RPA) framework and were based on Lindhard equation. Our simulations directly incorporated non-parabolicity of bulk 2D carriers spectrum, which was obtained by full 8-band k.p method. In the literature exists data that transport properties of HgTe QWs are explained by graphene-like screening. We provide the comparison of the screening function for the Schrodinger fermions in the inverted bands HgTe QW with the appropriate screening function for graphene monolayer with the Dirac fermions. In addition, the dependencies of HgTe-specific screening function on temperature, scattering wave-vector and frequency are studied with the purpose to study the transport properties under high-frequency radiation the QWs structures to be used as THz detectors. Plasmon frequencies of 2DEG in HgTe quantum well under study were calculated in the long-wavelength limit for T=77K.