Bulk Electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O

A. Chainani; T. Yokoya; Y. Takata; K. Tamasaku; M. Taguchi; T. Shimojima; N. Kamakura; K. Horiba; S. Tsuda; S. Shin; D. Miwa; Y. Nishino; T. Ishikawa; M. Yabashi; K. Kobayashi; H. Namatame; M. Taniguchi; K. Takada; T. Sasaki; H. Sakurai; E. Takayama-Muromachi

doi:10.1103/physrevb.69.180508

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Bulk Electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O

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Abstract

High-energy (h$ν$ = 5.95 keV) synchrotron Photoemission spectroscopy (PES) is used to study bulk electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O, the layered superconductor. In contrast to 3-dimensional doped Co oxides, Co $\it{2p}$ core level spectra show well-separated Co$^{3+}$ and Co$^{4+}$ ions. Cluster calculations suggest low spin Co$^{3+}$ and Co$^{4+}$ character, and a moderate on-site Coulomb correlation energy U$_{dd}\sim$3-5.5 eV. Photon dependent valence band PES identifies Co $\it{3d}$ and O $\it{2p}$ derived states, in near agreement with band structure calculations.

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A. Chainani, T. Yokoya, Y. Takata, K. Tamasaku, M. Taguchi, T. Shimojima, N. Kamakura, K. Horiba, S. Tsuda, S. Shin, D. Miwa, Y. Nishino, T. Ishikawa, M. Yabashi, K. Kobayashi, H. Namatame, M. Taniguchi, K. Takada, T. Sasaki, H. Sakurai, E. Takayama-Muromachi. 2004-02-27. Bulk Electronic structure of Na$_{0.35}$CoO$_{2}$.1.3H$_{2}$O. https://doi.org/10.1103/physrevb.69.180508

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