Raman studies of intrasubband plasmons in laterally modulated two-dimensional electron gases.

Abstract

We report an inelastic light-scattering study of the intrasubband plasmons of a single two-dimensional electron gas (2DEG) at a GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As heterointerface under a grating Schottky gate with a period comparable to the plasmon wavelength. Gaps appear in the plasmon dispersion relation because of the spatially periodic screening by the gate, and these are successfully modeled using a scattering matrix calculation of the electromagnetic response of the system. Biasing the gate periodically modulates the 2DEG carrier density, and has a striking effect on the plasmon dispersion relation that cannot be fully explained within the existing theoretical framework.