Thomas-Fermi-Dirac-von Weizsacker hydrodynamics in laterally modulated electronic systems

TL;DR

This paper investigates how collective plasma excitations in a two-dimensional electron gas are affected by lateral charge-density modulation, using a hydrodynamic model to analyze the transition from 2D to 1D behavior and its impact on FIR spectroscopy.

Contribution

It introduces a hydrodynamic approach based on the Thomas-Fermi-Dirac-von Weizsacker approximation to study modulated electron gases, capturing both equilibrium and dynamic properties.

Findings

Evolution of collective excitations from 2D to 1D regimes

Effect of modulation on power absorption in FIR spectroscopy

Consistent treatment of equilibrium and dynamical properties

Abstract

We have studied the collective plasma excitations of a two-dimensional electron gas with an arbitrary lateral charge-density modulation. The dynamics is formulated using a previously developed hydrodynamic theory based on the Thomas-Fermi-Dirac-von Weizsacker approximation. In this approach, both the equilibrium and dynamical properties of the periodically modulated electron gas are treated in a consistent fashion. We pay particular attention to the evolution of the collective excitations as the system undergoes the transition from the ideal two-dimensional limit to the highly-localized one-dimensional limit. We also calculate the power absorption in the long-wavelength limit to illustrate the effect of the modulation on the modes probed by far-infrared (FIR) transmission spectroscopy.