Elastic and optoelectronic properties of RbMF3 (M=Zn, Cd, Hg): A mBJ density functional calculation

Bonding nature as well as the structural, elastic, electronic and optical properties of cubic fluoroperovskites RbMF3 (M=Zn, Cd and Hg) compounds have been calculated using a full-potential augmented plane (FPLAPW) method within the density functional theory. The exchange-correlation potential was treated with the generalized gradient approximation of Wu and Cohen (WC-GGA) to calculate the total energy. Moreover, the modified Becke–Johnson potential (TB-mBJ) was also applied for the electronic and optical properties. It is found that lattice constant increases while bulk modulus decreases with the change of cation (M) in going from Zn to Hg in RbMF3 in accordance with the experimental results. The calculations of the electronic band structure, density of states and charge density show that these compounds have an indirect energy band gap (M–Г) with a mixed ionic and covalent bonding. The optical properties (namely: the absorption coefficient and the reflectivity) were calculated for radiation up to 45.0 eV.