Magnetic fluctuation and pairing instability controlled by the CoO6 distortion in the sodium cobalt oxide

Masahito Mochizuki*, Youichi Yanase, Masao Ogata

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We study how the CoO6 distortion along the c-axis affects the magnetic properties and superconductivity in the novel Co-oxide superconductor Nax CoO2 · y H2 O by analyzing the multiorbital Hubbard model using the fluctuation-exchange approximation. It is shown that through generating the trigonal crystal field, the distortion pushes the Co eg bands up and consequently gives rise to the hole-pocket Fermi surfaces, which have been predicted in the band calculations. As the distortion increases, the hole pockets are enlarged and the ferromagnetic fluctuation as well as the pairing instability increases, which is in good agreement with recent NQR results.

Original languageEnglish
Pages (from-to)875-877
Number of pages3
JournalPhysica B: Condensed Matter
Issue numberSPEC. ISS.
Publication statusPublished - 2006 May 1
Externally publishedYes


  • CoO distortion
  • Hole-pocket Fermi surface
  • Multiorbital Hubbard model
  • Na CoO · y H O

ASJC Scopus subject areas

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


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