Precise control of band filling in Na xCoO 2

Daisuke Yoshizumi, Yuji Muraoka, Yoshihiko Okamoto, Yoko Kiuchi, Jun Ichi Yamaura, Masahito Mochizuki, Masao Ogata, Zenji Hiroi

    Research output: Contribution to journalArticlepeer-review

    29 Citations (Scopus)


    Electronic properties of the sodium cobaltate Na xCoO 2 are systematically studied through a precise control of band filling. Resistivity, magnetic susceptibility and specific heat measurements are carried out on a series of high-quality polycrystalline samples prepared at 200 °C with Na content in a wide range of 0:35 ≤ x ≤ 0:70. It is found that dramatic changes in electronic properties take place at a critical Na concentration x* that lies between 0.58 and 0.59, which separates a Pauli paramagnetic and a Curie-Weiss metals. It is suggested that at x* the Fermi level touches the bottom of the a 1g band at the Γ point, leading to a crucial change in the density of states across x* and the emergence of a small electron pocket around the Γ point for x > x*.

    Original languageEnglish
    Article number063705
    Journaljournal of the physical society of japan
    Issue number6
    Publication statusPublished - Jun 2007


    • Band filling
    • Fermi surface
    • Magnetic susceptibility
    • Resistivity
    • Sodium cobaltate
    • Sommerfeld coefficient
    • Specific heat

    ASJC Scopus subject areas

    • Physics and Astronomy(all)


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