Laser-excited ultrahigh-resolution photoemission spectroscopy of superconducting Na0.35CoO2·1.3H2O

T. Shimojima, T. Yokoya, T. Kiss, A. Chainani, S. Shin, T. Togashi, C. Zhang, C. Chen, S. Watanabe, K. Takada, T. Sasaki, H. Sakurai, E. Takayama-Muromachi

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Abstract

We have studied the electronic structure near the Fermi level of the layered cobaltate superconductor Na0.35CoO2·1. 3H2O using laser-excited ultrahigh-resolution photoemission spectroscopy (PES). In the normal state, we observed the formation of a pseudogap with an energy scale of ∼20 meV. Across the superconducting transition, we observed the leading-edge shift at 3.5 K compared to that at 10 K, indicating superconducting gap (SC gap) opening having a gap value Δ of 0.5-0.7 meV. The energy scale of the SC gap is ∼20 times smaller than that of the pseudogap, suggesting the existence of competing order parameters at low temperatures.

Original languageEnglish
Pages (from-to)282-285
Number of pages4
JournalJournal of Physics and Chemistry of Solids
Volume67
Issue number1-3
DOIs
Publication statusPublished - 2006 Jan

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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