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Band gaps and electronic structure of alkaline-earth and post-transition-metal oxides

2010; American Physical Society; Volume: 81; Issue: 24 Linguagem: Inglês

10.1103/physrevb.81.245123

1550-235X

John A. McLeod, Regan G. Wilks, N. A. Skorikov, L. D. Finkelstein, M. Abu-Samak, E.Z. Kurmaev, A. Moewes,

Electronic and Structural Properties of Oxides

The electronic structure in alkaline-earth $Ae\text{O}$ $(Ae=\text{Be},\text{ }\text{Mg},\text{ }\text{Ca},\text{ }\text{Sr},\text{ }\text{Ba})$ and post-transition-metal oxides $Me\text{O}$ $(Me=\text{Zn},\text{ }\text{Cd},\text{ }\text{Hg})$ is probed with oxygen $K$-edge x-ray absorption and emission spectroscopy. The experimental data are compared with density-functional theory electronic-structure calculations. We use our experimental spectra of the oxygen $K$ edge to estimate the band gaps of these materials and compare our results to the range of values available in the literature. From the calculated partial density of states we conclude that the position of main $\text{O}\text{ }K$-edge x-ray emission feature in BeO, SrO, and BaO is defined by the position of the $np$ states of the cation while in the other oxides studied here the main $\text{O}\text{ }K$-edge x-ray emission feature is defined by the position of the $(n\ensuremath{-}1)d$ (for CaO) or $nd$ states of the cation.