Structural, electronics and optical properties of sodium based fluoroperovskites NaXF3 (X = Ca, Mg, Sr and Zn): First principles calculations

Highlights: • Structural, electronic and optical properties of sodium based fluoro perovskites were calculated. • NaCaF₃ has a highest peak for refractive index (n) and NaMgF₃ shows a dominating behavior in dielectric function. • NaMgF₃ has a dominating character in reflectivity and NaCaF₃ has a dominating character in absorption. • NaZnF₃ shows a semiconducting behavior, and NaCaF₃, NaMgF₃, and NaSrF₃ shows insulator behavior. A theoretical study to investigate the electronic, optical and structural properties of sodium-based cubic fluoro-perovskite NaXF₃ (where X = Ca, Mg, Sr, Zn), using density functional theory (DFT) based CASTEP (Cambridge Serial Total Energy Package) code with ultra-soft pseudo-potential USP plane wave and Perdew Burke Ernzerhof (PBE) exchange-correlation functional of Generalized Gradient Approximation (GGA), is reported. All of these compounds are found to be in a stable shape with a cubic pm3m structure, according to the findings. The results we discovered are consistent with the data that is already available. Calculations of the electronic band structure show that NaCaF₃, NaMgF₃ and NaSrF₃ have a direct and NaZnF₃ has an indirect band gap. Partial density of states (PDOS) and total density of states (TDOS) confirm the degree of electron localization in various bands. All four compounds' optical transitions were investigated by fitting the dispersion relation for the hypothetical dielectric function scale to the corresponding peaks. NaZnF₃ is semiconductor while the NaCF₃, NaMgF₃ and NaSrF₃ compounds have insulating behavior. The hypothetical part dispersion of the dielectric function reveals its wide range of energy transparency. As a result, it's possible that these materials may be used in optoelectronics to absorb ultraviolet light.