A DFT study of structural and electronic properties of some B12-based compounds under hydrostatic pressure

Using both standard DFT and GW approaches provided by VASP, we calculated in detail the structural properties and electronic band structures of alpha-B-12 and some B-12-based compounds in the rhombohedral structure. In addition, the changes in all physical properties calculated under hydrostatic pressure in the range of 0-350 GPa were investigated using the standard DFT method. It was observed that the lattice parameter and bond length values of alpha-B-12 and some B-12-based compounds examined in the pressure range of 0-350 GPa decreased, while the rhombohedral angle values of the compounds except alpha-B-12 increased. In the results obtained from the electronic characterization at ambient pressure, it was seen that the B13C2 and B13N2 compounds showed metallic properties, while the other compounds showed semiconductor properties. The variation of the indirect and direct band gaps of the compounds with pressure was investigated. While the electronic band gap of B12O2 increases with increasing pressure, the electronic band gap of other compounds with semiconductor properties tends to decrease with pressure. All computation results were compared with available other theoretical and experimental results in the literature.