Abstract
The electronic structure of several ternary oxides (SnTiO, PbTiO, BiTiO, and BiTiO) based on binary lone-pair oxides (SnO, PbO, and BiO) and a oxide (TiO) is investigated using soft x-ray spectroscopy and electronic-structure calculations. We find that the valence band of these ternary oxides is bounded by bonding (at the bottom of the valence band) and antibonding (at the top of the valence band) O 2p lone-pair (Sn , Pb , Bi ) hybridized states, while the conduction band is dominated by unoccupied Ti states. The existence of these two features is found to be independent of crystal structure or stoichiometry. The calculated hybridization in the bonding O lone-pair states is in reasonable agreement with the relative intensity of this feature in the measured x-ray emission spectra. The dominant influence on the conduction and the valence bands in the ternary oxides is due to different aspects of the electronic structure in the parent binary oxides, and we consequently find that the band gap of the ternary oxide is found to be a stoichiometric-weighed addition of the band gaps of the parent oxides.
- Received 29 June 2011
DOI:https://doi.org/10.1103/PhysRevB.85.195201
©2012 American Physical Society