First-principles study of the structural, electronic and thermal properties of CaLiF3

Density functional theory calculations have been performed to study the structural, electronic and optical properties of CaLiF3 cubic fluoroperovskite. Our calculations were carried out by means of the full-potential linearized augmented plane-wave method. The exchange-correlation potential is treated by the local density approximation and the generalized gradient approximation (GGA) (Perdew, Burke and Ernzerhof). Moreover, the alternative form of GGA proposed by Engel and Vosko is also used for band structure calculations. The calculated total energy versus volume allows us to obtain structural properties such as the lattice constant (a(0)), bulk modulus (B-0) and pressure derivative of the bulk modulus (B'(0)). Band structure, density of states and band gap pressure coefficients are also given. Our calculations show that CaLiF3 has an indirect band gap (R-Gamma). Following the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature and pressure effects on the lattice constant, bulk modulus, thermal expansion coefficient, Debye temperature and heat capacities are calculated.