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 t2g 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).