Magnetoplasma polaritons at the interface between a semiconductor and a metallic screen

An interface between a semiconductor and a highly conducting metallic screen supports polaritons that propagate at a right angle to a static magnetic field lying in the plane of the interface (Voigt geometry). In case of negligible plasmon-phonon interaction, there is a propagation window below the cyclotron frequency and another one above the hybrid cyclotron-plasma frequency. For a given orientation of the magnetic field, these modes propagate in opposite directions. In case of a polar semiconductor, there are three propagation windows whose limiting frequencies depend on the cyclotron, plasma, transverse-phonon, and longitudinal-phonon frequencies. These modes also exhibit nonreciprocality with respect to their direction of propagation. Effects of damping and of the finite conductivity of the metallic screen, and the possibility of experimental detection of the predicted modes are discussed.