The electronic and optical properties of the fluoroperovskite XLiF3 (XÂ =Â Ca, Sr, and Ba) compounds

Structural, electronic, and optical properties of the fluoroperovskite XLiF3 (X = Ca, Sr and Ba) compounds are studied using the full potential linearized augmented plane wave method as implemented in the Wien2k code. The exchange-correlation potential is treated by the generalized gradient approximation with in the scheme of Perdew, Burke and Ernzerhof (GGA-PBE). In these calculations we show that these compounds have direct energy band-gap (Γ-Γ). We calculate the dielectric function, the refractive index, the extinction coefficient, the absorption coefficient, and the reflectivity. All compounds in the optical response are shifted toward higher energies as we moved from Ca to Ba, in agreement with the band structured. Our calculated optical properties show considerable anisotropy at low and high energies.