Simple principles were proposed for predicting qualitatively the chemical trends of oxygen-vacancy levels in binary metal oxides by analyzing the atomic wave-function characteristics of the conduction-band minimum. It was shown that, if the conduction-band minimum was a metal-oxygen anti-bonding state due to either s-s coupling, p-p coupling, or p-d coupling then in general the oxygen-vacancy level was deep. The stronger coupling led to deeper levels. If the conduction-band minimum was a non-bonding d state, then the oxygen vacancy level could be shallow. These principles were confirmed by the calculated trends of oxygen vacancy levels in representative binary metal oxides using hybrid density-functional method.

Prediction of the Chemical Trends of Oxygen Vacancy Levels in Binary Metal Oxides. W.J.Yin, S.H.Wei, M.M.Al-Jassim, Y.Yan: Applied Physics Letters, 2011, 99[14], 142109