Resonance photoelectron spectroscopy of TiX2 (X = S, Se, Te) titanium dichalcogenides

The photoelectron valence band spectra of TiS 2 , TiSe 2 , and TiTe 2 dichalcogenides are investigated in the Ti 2 p -3 d resonance regime. Resonance bands in the vicinity of the Fermi energy are found for TiS 2 and TiTe 2 . The nature of these bands is analyzed based on model calculations of the density of electronic states in TiS 2 , TiSe 2 , and TiTe 2 compounds intercalated by titanium atoms. Analysis of experimental data and their comparison with model calculations showed that these bands have different origins. It is found that the resonance enhancement of an additional band observed in TiS 2 is explained by self-intercalation by titanium during the synthesis of this compound. The resonance enhancement in TiTe 2 is caused by occupation of the 3 d band in Ti.