Theoretical study of structural, elastic and thermodynamic properties of CZTX (X = S and Se) alloys

By means of first-principles calculation approach, structural parameters, elastic and thermodynamic properties of Copper-Zinc-Tin-(Sulphide, Selenide) or Cu2ZnSnX4 (X = S and Se) alloys for the kesterite (KS) and stannite (ST) types have been investigated. The calculated lattice parameters are in good agreement with experimental reported data. The elastic constants are calculated for both types of both compounds using the static finite strain scheme; the pressure dependence of elastic constants is predicted. The bulk modulus, anisotropy factor, shear modulus, Young's modulus, Lame's coefficient and Poisson's ratio have been estimated from the calculated single crystalline elastic constants. The analysis of B/G ratio shows that Cu2ZnSnX4 or CZTX compounds behave as ductile. Through quasi-harmonic approximation, the temperature dependence of some thermodynamic functions and lattice heat capacity of both compounds for both types have been performed. (C) 2013 Elsevier B. V. All rights reserved.