The electronic structure of Ca-intercalated superconducting graphite CaC6

H. Okazaki, R. Yoshida, K. Iwai, K. Noami, T. Muro, T. Nakamura, T. Wakita, Y. Muraoka, M. Hirai, F. Tomioka, Y. Takano, A. Takenaka, M. Toyoda, T. Oguchi, T. Yokoya

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We have measured Ca-intercalated graphite superconductor CaC6 (Tc = 11.2 K) by soft X-ray photoemission spectroscopy in order to understand the electronic structure. For the valence band, we observed several structures that correspond to those of calculated density of states with the partial density of states of Ca 3d at the Fermi level (EF). We also observed core level spectra that are a very large asymmetric Ca 2p and asymmetric C 1s for CaC6, suggesting the existence of conduction electrons derived from Ca 3d and a charge transfer from Ca to graphene layer. These results provide spectroscopic evidence for PDOS of Ca 3d at EF. From a comparison of electronic structure of CaC6 and other graphite intercalation compounds (GICs), we found the difference between CaC6 and other superconducting GICs, which provides deeper understanding of the superconductivity of CaC6.

Original languageEnglish
Pages (from-to)1041-1044
Number of pages4
JournalPhysica C: Superconductivity and its applications
Issue number15-20
Publication statusPublished - Oct 15 2009


  • Electronic structure
  • Graphite intercalation compounds
  • Soft X-ray photoemission spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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