Ab initio study of the structural, electronic and optical properties of the fluoropervskite SrXF3 (X = Li, Na, K and Rb) compounds

An ab initio full-potential linear augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA), as implement in Wien2k code, has been used to study the structural, electronic and optical properties of the fluoropervskite SrXF3 (X = Li, Na, K and Rb) compounds. The calculated lattice constant and bulk modulus are in agreement with previous calculations. The calculated band structures show a direct band-gap (Γ–Γ). The contribution of the different bands is analyzed from the total and partial density of states curves. The dielectric function, refractive index and extinction coefficient are calculated. The origin of some of the peaks in the optical spectra is discussed in terms of the calculated electronic structure. The values of static dielectric constant ε1(0) is found to be increasing with a decrease in the energy band-gap.