Heavy thallium based fluoroperovskite TlAF₃ (A = Ge, Sn and Pb) compounds: a computational investigation

The use of heavy elements to build a stable system increases the effective atomic number, making it useful in a variety of applications such as radiation detection and shielding. This study reports the density functional theory (DFT) based investigations on new Thallium based heavy fluoroperovskites TlAF₃ (A = Ge, Sn and Pb). These compounds have a cubic perovskite structure with optimal lattice constants ranging from 4.49 to 4.85 Å. Electronic behaviors of the compounds is found to be insulating with the maximum band gap of up to 1.90 eV, having indirect band nature. In all investigated compounds, the fluorine atom provides a significant number of electronic states to the valence and conduction bands. The optical activity is evaluated by determining the refractive index, extinction coefficient, optical conductivity, reflectivity, and absorption coefficients up to photon energies of 20 eV. The properties of present compounds are being reported for the first time.