PACS. 79.60.Bm Clean metal, semiconductor, and insulator surfaces – 78.70.Dm X-ray absorption spectra – 71.30.+h Metal-insulator transitions and other electronic transitions
Springer Online Journal Archives 1860-2000
Abstract: We studied the changes in the electronic structure of SrTi1-xRuxO3 across the metal-insulator transition. The parent compound, SrTiO3, is a well known diamagnetic insulator; whereas the doped compound, SrTi1-xRuxO3, becomes a ferromagnetic metal above x C = 0.35. The techniques used in the study were photoemission (PES) and O 1 s X-ray absorption (XAS) spectroscopy. The experimental spectra were analyzed in terms of band structure and Hubbard model calculations. The PES and XAS spectra of SrTi1-xRuxO3 show the Ru 4 d bands growing in the band gap of SrTiO3 . The analysis in terms of the Hubbard model indicates that the Ti 3 d and Ru 4 d bands are mostly decoupled. This suggests that the metal-insulator transition is a percolation transition like that of metals embedded in a rare gas matrix. Electron correlation effects are present in this system, but they do not seem to play a major role in the transition.
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