Surface Phonon-Polaritons in Slabs of Ternary Mixed Crystals

Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual boundary conditions. The numerical results of the surface phonon-polariton frequencies as functions of the wave-vector and thickness for slabs of ternary mixed crystals AlxGa1-xAs, Znx Cd1-x S,and Gax In1-x N are obtained and discussed. It is shown that there are four branches of surface phonon-polaritons in slab systems. The “two-mode” and “one-mode” behaviors of surface phonon-polaritons are also shown in their dispersion curves.

Exciton-polaritons in ternary mixed crystals

In this paper the bulk exciton polaritons in ternary mixed crystals （TMCs） are investigated in the Born-Huang approximation. The numerical results of the polariton frequencies as functions of the wave-vector and the compositions for ternary mixed crystals AlxGa1-xAs, CdxZn1-xSe, and AlxGa1-xN are obtained and discussed. The new dispersion characteristics for exciton-polaritons in TMC systems are found in comparison with binary crystals. The splitting of the two branches of exciton-polariton frequencies varies nonlinearly with the composition of TMCs and has a minimum in the long-wavelength range.

Interface phonon-polaritons in quantum well systems of polar ternary mixed crystals

The interface phonon-polaritons in quantum well systems consisting of polar ternary mixed crystals are investi-gated. The numerical results of the interface phonon-polariton frequencies in the GaAs/AlxGa1-xAs, ZnSxSe1-x/ZnS, and ZnxCd1-xSe/ ZnSe quantum well systems are obtained and discussed. It is shown that there are six branches of interface phonon-polariton modes distributed in three bulk phonon-polariton forbidden bands in the systems. The electric fields of interface phonon polaritons are also presented and show the interface locality of the modes. The effects of the ＇two-mode＇ and ＇one-mode＇ behaviours of the ternary mixed crystals on the interface phonon-polariton modes are shown in the dispersion curves.

Effects of built-in electric field and donor impurity on linear and nonlinear optical properties of wurtzite InxGa1-xN/GaN nanostructures

The linear and nonlinear optical absorption coefficients(ACs)and refraction index changes(RICs)of 1s-1p,1p-1d,and 1f-1d transitions are investigated in a wurtzite InxGa1-xN/GaN core-shell quantum dot(CSQD)with donor impurity by using density matrix approach.The effects of built-in electric field(BEF),ternary mixed crystal(TMC),impurity,and CSQD size are studied in detail.The finite element method is used to calculate the ground and excited energy state energy and wave function.The results reveal that the BEF has a great influence on the linear,nonlinear,and total ACs and RICs.The presence of impurity leads the resonant peaks of the ACs and RICs to be blue-shifted for all transitions,especially for 1s-1p transition.It is also found that the resonant peaks of the ACs and RICs present a red shift with In-composition decreasing or core radius increasing.Moreover,the amplitudes of the ACs and RICs are strongly affected by the incident optical intensity.The absorption saturation is more sensitive without the impurity than with the impurity,and the appearance of absorption saturation requires a larger incident optical intensity when considering the BEF.