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 journalArticle

27 Citations (Scopus)

Abstract

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
Volume76
Issue number6
DOIs
Publication statusPublished - 2007 Jun 1
Externally publishedYes

Keywords

  • 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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    Yoshizumi, D., Muraoka, Y., Okamoto, Y., Kiuchi, Y., Yamaura, J. I., Mochizuki, M., Ogata, M., & Hiroi, Z. (2007). Precise control of band filling in Na xCoO 2 journal of the physical society of japan, 76(6), [063705]. https://doi.org/10.1143/JPSJ.76.063705