Contribution of electronic structure to the large thermoelectric power in layered cobalt oxides

Tsunehiro Takeuchi, Takeshi Kondo, Tsuyoshi Takami, Hirofumi Takahashi, Hiroshi Ikuta, Uichiro Mizutani, Kazuo Soda, Ryoji Funahashi, Masahiro Shikano, Masashi Mikami, Syunsuke Tsuda, Takayoshi Yokoya, Shik Shin, Takayuki Muro

Research output: Contribution to journalArticlepeer-review

162 Citations (Scopus)


With a strong help of high-resolution photoemission spectroscopy we demonstrate in this paper that the large thermoelectric power observed in the layered cobalt oxides, such as Ca3Co4O9, Na0.6CoO2, and Bi2Sr2Co2O9, can be well accounted for with the Boltzmann-type metallic electrical conduction. An intense peak with 1.5-2 eV in width was observed in the photoemission spectra with its center at 1.0 eV below the Fermi level EF in these compounds. The density of states at EF is finite but negligibly small at room temperature, because EF is located near the high-energy edge of this narrow band. We calculated thermoelectric power S using the Boltzmann transport equation with the electronic structure near EF determined by the photoemission measurement. The calculated S shows fairly good consistency with the measured value both in its magnitude and the temperature dependence.

Original languageEnglish
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number12
Publication statusPublished - Mar 19 2004
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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