Ground state structures in the polonium based II-VI compounds

We have performed ab-initio self-consistent calculations using the full-potential linear augmented plane-wave method to investigate the structural and the electronic properties of the less known II-VI compounds: ZnPo, CdPo, and HgPo. Total energy calculations of the cubic zinc-blende, wurtzite, rocksalt, cesuim chloride, orthorhombic Cmcm, and tetragonal PbO phases are investigated. Ground state parameters are computed, and compared with available theoretical and experimental works. The zinc-blende structure is found to be the ground state phase of ZnPo and CdPo, while HgPo prefers the tetragonal PbO structure. The calculated band structure of II-Po shows features that differ considerably from those of typical II-VI semiconductors. In particular we found an inverted band gap, reflecting a semi-metallic character for these compounds.