Density functional theory study of bulk platinum monoxide

The ground state electronic structure of platinum monoxide (PtO) has been calculated using density functional theory (DFT) with periodic boundary conditions and Gaussian type orbitals. Several DFT exchange-correlation functionals, including a hybrid functional based on a screened Coulomb potential for exact exchange have been used. Our study reveals that functionals based on the generalized gradient approximation (GGA) or meta-GGA do not give qualitatively different results from those of the local spin density approximation, predicting PtO to be metallic, whereas the hybrid functional predicts a semiconductor with a band gap of 0.86 eV. A reduced band gap of 0.56 eV is found in the oxygen deficient PtO_0.9 system.