LAUSR

Abstract A theoretical study of structural and elastic properties of Cu2MgSnSe4(CMTSe) and Cu2MgSnTe4 (CMTTe) compounds in stannite (ST), kesterite (KS), primitive-mixed CuAu (PMCA) and Wurtzite-Stannite (WS) structures is presented, by using the functional density theory in the framework of FP-LAPW + lo method within the generalized gradient approximation, based on Perdew 2008 functional (GGA-PBEsol). For each phase, the structural parameters, bulk modulus, and its pressure derivative are calculated. The relative stability of these phases is also discussed. In addition, the elastic constants have been calculated in order to examine the mechanical stability of all phases. Moreover, the anisotropy factor, shear modulus, Young's modulus, Lame's coefficient and Poisson's ratio have been estimated from the obtained single crystalline elastic constants. The thermodynamic properties such as the heat capacities, the coefficient of thermal expansion and the Debye temperature, in the pressure range 0–15 GPa and the temperature range from 0 to 1300 K, of the ground state structure are also investigated for the three materials Cu2MgSnS4 (CMTS), CMTSe, and CMTTe. The obtained results are compared with available experimental data and with other theoretical calculations.