Structural, Mechanical and Thermodynamic Properties of Cu2CoXS4 (X = Si, Ge, Sn) Studied by Density Functional Theory

Abstract

We have investigated the Structural, mechanical and thermodynamic properties of Cu₂CoXS₄ (X = Si, Ge, Sn) by using the density functional theory method. In this paper, we used GGA-PBE functional to find the equilibrium structural parameters and to calculate the elastic properties. The Mulliken population analysis indicates the bonds between S atoms and other three atoms in Cu₂CoXS₄ (X = Si, Ge, Sn) exhibit the feature of covalent bond. Furthermore, the calculated elastic constants prove the mechanical stability of Cu₂CoXS₄ (X = Si, Ge, Sn) in I\(\bar 4\)2m structure. The results are given for B/G and A^U reveal Cu₂CoXS₄ (X = Si, Ge, Sn) can behave as a ductile and elastic material. Finally, the heat capacity, thermal expansion, entropy and Debye temperature are also reported at the different pressures (0~50 GPa) and temperatures (0~1000 K).