Thermodynamic and elastic properties of AgInSe2 and AgInTe2

The specific heat at constant volume as a function of temperature, the elastic constants, compressibility coefficients, and bulk moduli of AgInSe2 and AgInTe2 crystals with a chalcopyrite structure have been calculated in terms of the density functional theory using the pseudopotential method. A comparison of the calculated specific heat for the tellurium compound with the results of measurements has demonstrated good agreement between theory and experiment. The bulk moduli of the AgInSe2 and AgInTe2 crystals calculated from first principles (60.4 and 50.1 GPa, respectively) somewhat exceed the results available in the literature, which were obtained earlier from approximate semiempirical formulas.