Anomalous metallic state with strong charge fluctuations in BaxTi8 O16+δ revealed by hard x-ray photoemission spectroscopy

S. Dash, Tomomasa Kajita, M. Okawa, T. Saitoh, E. Ikenaga, N. L. Saini, Takuro Katsufuji, Takashi Mizokawa

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    We have studied a charge-orbital driven metal-insulator transition (MIT) in hollandite-type BaxTi8O16+δ by means of hard x-ray photoemission spectroscopy (HAXPES). The Ti 2p HAXPES indicates strong Ti3+/Ti4+ charge fluctuation in the metallic phase above the MIT temperature. The metallic phase is characterized by a power-law spectral function near the Fermi level which would be a signature of bad metal with non-Drude polaronic behavior. The power-law spectral shape is associated with the large Seebeck coefficient of the metallic phase in BaxTi8O16+δ.

    Original languageEnglish
    Article number165116
    JournalPhysical Review B
    Issue number16
    Publication statusPublished - 2018 Apr 10


    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

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