Effect of Thickness of Slabs on the Surface and Interface Phonon-Polaritons in Four Layer Systems Consisting of Polar Ternary Mixed Crystals

Surface and interface phonon-polaritons in four layer heterostructure systems consisting of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation,based on the Maxwell's equations with the usual boundary conditions.The numerical results of the surface and interface phonon-polariton frequencies as functions of the thickness of slabs in the GaAs/Al0.4Ga0.6As heterostructure systems are obtained and discussed.It is shown that there are seven branches of surface and interface phonon-polariton modes in heterostructure systems,and the energies of surface or interface modes of the slab change with the thickness of slab,however,the other polariton modes almost not change.