Surface and interface phonon-polaritons in bilayer systems of polar ternary mixed crystals

Abstract

The surface and interface phonon-polaritons in bilayer systems consisting of polar ternary mixed crystals are investigated in the modified random-element-isodisplacement model and the Born–Huang approximation, based on the Maxwell’s equations with the boundary conditions. The numerical results of the surface and interface phonon-polariton frequencies as functions of the wave vector and the composition of the ternary mixed crystals in GaAs/AlxGa1−xAs, ZnS/ZnSxSe1−x, and ZnSe/ZnxCd1−xSe bilayer systems are obtained and discussed. It is shown that there are six branches of surface and interface phonon-polaritons in binary/ternary systems. The effects of the “two-mode” and “one-mode” behaviors of the ternary mixed crystals on the surface and interface phonon-polariton modes are shown in the dispersion curves. The electric fields of surface and interface phonon-polaritons are also presented for various cases.