The cobalt oxide superconductor NaxCoO2Â•yH2O is studied by angle-resolved photoemission spectroscopy. We report the Fermi surface (FS) topology and electronic structure near the Fermi level (EF) in the normal state of NaxCoO2Â•yH2O. Our result indicates the presence of the hexagonal FS centered at the Î" point, while the small pocket FSs along Î"-K direction are absent, similar to NaxCoO2. The top of the eg band, which is expected in band calculations to form the small pocket FSs, extends to within 30meV below EF, closer to EF than in NaxCoO2. We discuss its possible role in superconductivity, comparing with other experimental and theoretical results.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)