Collective excitations and electrodynamic behavior of electrons in a three-layer structure

Abstract

A unified theoretical approach appropriate for investigating properties of two-dimensional electron systems, e.g., in the surface-space-charge layer of a metal-oxide-semiconductor junction or above the surface of liquid helium in a metal-helium-vapor system is presented. As an application of the theory we explore the possibility to study microscopically and macroscopically collective excitations in these and other complex geometries. Special emphasis is put on the implications of the theory to be drawn from the localization of the electron motion both perpendicular to the interface which is, e.g., the case at sufficiently low temperatures and parallel to it possibly occuring, e.g., at low densities and high static magnetic fields oriented perpendicular to the interface. It is illustrated why intrinsic defects in the crystalline structure of such systems are to be expected and that they should affect their equilibrium and transport properties, especially, in the vicinity of the transition to a liquid-like phase.