Magnetoplasmon excitations in a periodically modulated two-dimensional electron gas.

Abstract

The dielectric response of a laterally modulated two-dimensional electron gas in a perpendicular magnetic field is studied fully quantum mechanically in the random-phase approximation. The ground-state wave functions are obtained self-consistently in the Hartree approximation. Parameters appropriate for a laterally microstructured GaAs-${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$As interface (modulation period 5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ cm, electron density 2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$, magnetic field 10 T) are chosen. The dielectric function, with local-field effects included, is calculated, and results for the magnetoplasmon dispersion for wave vectors parallel and perpendicular to the one-dimensional modulation potential are presented.