Interplay between Mott physics and Peierls physics in hollandite-type vanadates with a metal-insulator transition

Y. Ishige, T. Sudayama, Y. Wakisaka, T. Mizokawa, H. Wadati, G. A. Sawatzky, T. Z. Regier, M. Isobe, Y. Ueda

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17 Citations (Scopus)


We report an x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) study on K2V8-xTixO 16 (x=0.0, 0.3, and 4.0) in which the metal-insulator transition (MIT) and the tetragonal-to-monoclinic structural transition show different responses against the Ti doping. The spectral change of V 2p XAS across the MIT is similar to that observed in VO2, indicating that the V-V pairing is responsible for the MIT. In the insulating phase, the V 2p XPS spectra are split into the V3+ and V4+ features showing the localized character of the V 3d electrons. In addition, the V 2p XAS spectra of the monoclinic insulating phase suggest that the V-V pairing is weakened, and, instead, the V3+-V4+ coupling is strengthened by orbital ordering. In contrast to VO2, the existence of the V3+ component in K2V8-xTixO16 gives additional orbital instability in the insulating phase, which competes with the V-V pairing.

Original languageEnglish
Article number125112
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number12
Publication statusPublished - 2011 Mar 22


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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