First-principles investigations of Ba2NaIO6 double Perovskite semiconductor: Material for low-cost energy technologies

The investigations on the physical properties of the Ba2NaIO6 double perovskite, in this work, are presented. These investigations are carried out using WIEN2k computational code realized within the density functional theory (DFT) approach and at the level of the generalized gradient approximation (GGA) of exchange correla-tional functional as parameterized by Perdew Burke and Erenzerhof (PBE) beside employing modified Becke-Johnson (mBJ) as well as hybrid Heyd-Scuseria-Ernzehof (HSE) potentials. The results obtained for structural parameters have been found well-matching to the available literature. The obtained results of the electronic structure indicate the Ba2NaIO6 has a direct bandgap semiconductor at the center of the Brillouin zone (T). We also presented a detailed study on its optical properties. Concerning its mechanical properties, the results of the bulk, Young, and shear modulus (G), the anisotropic factor (A), and Poisson's ratio (nu) are obtained using the first-principles results for the elastic constants. The sound velocities and Debye temperature are also determined for this compound. Furthermore, calculations of its transport properties demonstrate its p-type semiconductor nature. The results of the reported parameters show that Ba2NaIO6 double perovskite is a suitable base material for optoelectronic devices particularly working for the infrared region as well as for thermoelectric applications.