The influence of electromagnetic field on plasma oscillations in two-dimensional electronic systems with superstructure

The influence of high-frequency electric field on plasma oscillations in a system, consisting of two two-dimensional electronic gases, one of which represents a system with periodic potential (superstructure), and another one has a parabolic energy spectrum of charge carriers, is investigated. For the case of high temperatures ($\Delta\ll T$, $\Delta$ is the conduction minizone width, and $T$ is the temperature in energy units) the spectrum of the coupled plasmons $\omega(k)$, where $k$ is the wave number, is calculated. The frequency of the coupled plasmons is found to be an oscillating function of the electromagnetic field amplitude. The calculations are performed on the basis of the quantum theory of plasma oscillations in a random-phase approximation.