Predicting the band gap of ternary oxides containing 3d10and 3d0metals

Abstract

We present soft x-ray spectroscopy measurements and electronic structure calculations of ZnTiO${}_{3}$, a ternary oxide that is related to wurtzite ZnO and rutile TiO${}_{2}$. The electronic structure of ZnTiO${}_{3}$ was calculated using a variety of exchange-correlation functionals, and we compare the predicted band gaps of this material obtained from each functional with estimates from our experimental data and optical gaps quoted from the literature. We find that the main hybridizations in the electronic structure of ZnTiO${}_{3}$ can be predicted from the electronic structures of the two binary oxides. We further find that ZnTiO${}_{3}$ has weaker O 2p-Zn 3d repulsion than in ZnO, resulting in a relatively lower valence band maximum and consequently a larger band gap. Although we find a significant core hole shift in the measured O $K$ XAS of ZnTiO${}_{3}$, we provide a simple empirical scheme for estimating the band gap that may prove to be applicable for any $d$${}^{10}$-$d$${}^{0}$ ternary oxide, and could be useful in finding a ternary oxide with a band gap tailored to a specific energy.