First-principles investigations of physical properties of CdXP2 (X = Si, Ge, and Sn) ternary chalcopyrite.

In the present work, we present a theoretical study of the physical properties of ternary CdXP₂ (X: Si, Ge, and Sn) chalcopyrite materials through the full-potential linearized augmented plane wave method. The generalized gradient approximations of Perdew, Burke, and Ernzerhof have been used to handle the exchange–correlation potential. Moreover, the electronic structure calculations are further improved through the modified Becke Johnson potential. Our calculations for the structural parameters of the studied compounds are found well-matching with the literature. Investigations of the electronic properties of the considered compounds have been executed through the calculation of the band structure. We observe that our compounds are semiconductors characterized by a direct energy gap between the Γ-Γ symmetry points. The optical constants, including the dielectric functions, were calculated for energy up to 30 eV. Using the GIBBS program, which is based on the quasi-harmonic model of Debye, we have investigated the thermodynamic behavior of the considered chalcopyrite under pressure and temperature effects. The variation of the volume, bulk modulus, and temperature-dependent Debye temperature and heat capacities for different pressures are estimated. [ABSTRACT FROM AUTHOR]