Collective charge density excitations in two-component one-dimensional quantum plasmas: Phase fluctuation mode dispersion and spectral weight in semiconductor quantum wire nanostructures

TL;DR

This paper analyzes collective charge density excitations in two-component 1D quantum plasmas within semiconductor quantum wires, examining mode dispersion, spectral weight, impurity effects, and interwire tunneling, with implications for experimental observation.

Contribution

It provides a comprehensive calculation of collective modes, spectral weights, and impurity effects in two-component 1D quantum plasmas, including effects of tunneling and local field corrections.

Findings

OP mode carries most spectral weight at long wavelengths

AP mode remains observable at finite wave vectors

Impurity scattering overdamps modes below a critical wave vector

Abstract

Collective charge density excitation spectra of both a spatially separated two-component quasi-one dimensional (1D) quantum plasma, as existing in a semiconductor double quantum wire structure, and a 1D homogeneous electron-hole plasma, as appropriate for a photoexcited semiconductor quantum wire system, are calculated within the two-component random-phase-approximation. We also investigate the effect of impurity scattering on the collective mode dispersion and damping, and calculate the collective mode spectral weight by obtaining the dynamical structure factor. We find that both OP and AP modes are overdamped by impurity scattering below some critical wave vector. We find that in the long wavelength limit the spectral weight is carried mostly by the OP, but the spectral weight of the undamped AP mode at finite (but not too large) wave vectors is comparable with that of the OP mode, making it viable to observe the AP mode in semiconductor quantum wire systems. The effect of the interwire electron tunneling in a biwire system on the collective charge density excitation spectra is also studied. We discuss the mode dispersion and damping from an effective Luttinger liquid perspective as well and in some cases include local field corrections in our calculations.