Electronic structure and core level photoemission spectra in TiO2compounds

Abstract

The authors first calculate a standard 'linear muffin-tin orbital' band structure (including combined correction and exchange correlation) for TiO₂ compounds in rutile structure. The outcoming bands, especially the last valence (mostly O 2p states) and first conduction (mostly Ti t_2g states) bands, are fairly hybridized. The authors then use the information contained in the previously considered density of states to build a simplified electronic structure of TiO₂ in order to interpret the Ti core-level photoemission spectra in the simplest way. To achieve this they use the filled band impurity Anderson model which treats the Ti 3d electron-electron correlations and they incorporate the 3d-core hole interaction. Although the model is quite crude from the point of view of the one-electron band structure calculation, it contains many-electron features which can be solved exactly and which are sufficient to roughly describe the satellite structure observed in the core photoemission spectra of TiO₂ (as well as related insulating compounds like Li₄3/Ti₅3/O₄ or TiF₄, for example).