Abstract
A review is given of experimental studies of infrared absorption, reflection, and Raman scattering of light on single crystals of I!--IV--V2 compounds. A rigid ion model is discussed as applied to the calculation of phonon spectra of ternary compounds with the chalcopyritetype lattice. In the simplest version of the model, short-range forces in the nearestneighbor approximation are given with the help of three parameters; Coulomb forces in the model of unpolarized ions are determined by two parameters. The dependence of phonon spectra on the ratio of cation masses is analyzed: a similarity between phonon spectra of ternary compound with similar cation masses and analogous binary compounds, placed in the Brillouin zone of chalcopyrite, as well as significant qualitative differences between spectra of binary and ternary semiconductors for a significant difference in cation masses is indicated. The calculated frequency density function, taken with a double scale g(2~), describes qualitatively the full symmetry component of the Raman scattering spectrum of second order. From the analysis of calculated elastic constants is has been established that in a number of ternary compounds a tendency is observed for decrease of elastic constants as the average atomic number is increased. Anisotropy of propagation of elastic waves in ternary compounds is analyzed. From the comparison of theoretical and experimental temperature dependences of the specific heat it has been shown that the Debye model does not describe experiment as well as the model which takes into account the real structure of the phonon spectrum.
Published Version
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