Screening and oscillations in a spatially modulated 2D electron gas

Abstract

Thescreeningofaone-dimensionalpotentialreliefbya2~elenrongasandplasmaoscillations is investigated for the case of cosine-like extemal potentials. "he analytical solution of the screening problem provides an opportunity for the development of qualified numerical procedures for linear oscillations within the framework of the hydrodynamical model. A simple analytical expression is obtained for the frequency of a zero-wave vector plasmon as a function of electron concentration and potential amplitude. A strong frequency drop at the critical point of concentration between linear and nan-linear screening regimes, which was observed experimentally, is explained. In the vicinity of the critical concentration the asymptotical expressions are derived, which hold for any smooth periodical potential.