DFT-based ab initio study of the electronic, optical and thermodynamics properties of Al based fluoro-perovskite AlMF3 (M= Ca and cd)

Ab initio Density Functional Theory (DFT) calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation and Hubbard-U term were used to investigate the structural, elastic, electronic, and optical properties of Al-based fluoro perovskite compounds AlMF 3 (M = Ca and Cd). With a careful investigation of the contribution from various bands utilizing total and partial density of state curves, electronic band structure analysis identified AlCaF 3 and AlCdF 3 as direct band gap materials. Calculations of optical spectra spanning 0 to 40 eV were done, including real and imaginary parts of the dielectric function, optical reflectivity, absorption coefficient, optical conductivity, refractive index, and extinction coefficients. Because of their unique optical properties, the materials have potential applications in optoelectronic devices.