High-energy (hv = 5.95 keV) synchrotron photoemission spectroscopy (PES) is used to study bulk electronic structure of Na0.35CoO2 · 1.3H2O, the layered superconductor. In contrast to three-dimensional doped Co oxides, Co 2p core level spectra show well-separated Co3+ and Co4+ ions. Cluster calculations suggest low-spin Co3+ and Co4+ character, and a moderate on-site Coulomb correlation energy Udd∼3-5.5 eV. Photon dependent valence band PES identifies Co 3d and O 2p derived states, in near agreement with band-structure calculations.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - May 2004|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics