Structural phase transition, elastic properties and electronic properties of chalcopyrite CuAlX2 (X = S, Se, Te)

The density functional theory calculations of structural phase transition, elastic constants and electronic structure of the CuAlX2 (X = S, Se, Te) have been reported using the full potential linear muffin-tin orbital (FP-LMTO). In this approach, the local density approximation is used for the exchange-correlation potential. Results are given for lattice constant, bulk modulus, and its pressure derivative, band structure, density of states and pressure dependence of energy gaps. We note that these compounds are semiconductors with direct energy gaps. The valence-band maximum and conduction-band minimum are located at Γ. Our results are compared with previous theoretical calculations and experimental data. The elastic constants at equilibrium in BCT structure are also determined.