First-principle study on the relationship between elasticity and thermodynamic properties of CuInX2 (X = S, Se, and Te) under high temperature and high pressure

Abstract

CuInX2(X = S, Se, Te) belonging to the chalcopyrite semiconductor materials has potential applications in optical-electronic fields. Temperature and pressure are important factors in changing the crystal structure and properties of materials. However, the elasticity and thermodynamic properties and intrinsic relationship need to be further investigated in high-temperature and high-pressure working environments. Based on the first principles of density functional theory (DFT), the bulk modulus (B), heat capacity, thermal expansion coefficient (a) and Debye temperature (ΘD) has been systematically investigated within the range of temperature (0–1000 K) and pressure (0–20 GPa). The elastic constants prove the mechanical stability of the crystal. Within the temperature and pressure ranges studied, B and ΘD increases as pressure increases. The influence of pressure on the properties of CuInX2(X = S, Se, Te) is stronger than that of temperature. At given pressure and given temperature, B and V, as well as ΘD and B follow a linear relationship. These linear relationships of mechanics and thermodynamic parameters with different temperature and pressure, offering a useful design strategy for efficient chalcogenides materials and save time and experiment preparation cost. These results provide a foundation understanding of the basic properties of CuInX2(X = S, Se, Te) and future device development in extreme environments.