Raman and infrared studies of optical phonons in Zn1-xMnxTe mixed crystals

Abstract
Raman and infrared reflectivity spectra of Zn1-xMnxTe mixed crystals were measured in the composition range 0<x<0.15. The experimental data obtained are analysed using the modified random-element isodisplacement model. It is found that the x dependence of the optical-phonon frequencies displays an intermediate behaviour between one- and two-mode type. A satisfactory agreement of the model with the experimental results is obtained only after the inclusion of force constants due to next-nearest neighbours.
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