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Photoemission and x-ray absorption study of the two-dimensional triangular lattice superconductor Na0.35CoO2·1.3H2O

Masato Kubota, Kazunori Takada, Takayoshi Sasaki, Hiroshi Kumigashira, Jun Okabayashi, Masaharu Oshima, Motohiro Suzuki, Naomi Kawamura, Masafumi Takagaki, Katsutoshi Fukuda, Kanta Ono

DOI 10.1103/PhysRevB.70.012508 · Physical Review B

T1

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Abstract

We have investigated the electronic structure of a triangular lattice superconductor Na0.35CoO2·1.3H2O (Tc∼5K) by photoemission and x-ray absorption spectroscopy. The Co 2p x-ray absorption and Co 2p–3d resonant photoemission clarified that the valence band near the Fermi level is mainly constructed by the narrow Co 3d t2g states at the binding energy of 1.0eV with the low-spin configuration. In the resonant photoemission, Auger features coexist with the resonant enhancements, while the charge-transfer satellites are observed in the photoemission spectra of a Co 2p core levels. It is also expected that the narrow t2g band reflects on the importance of an electron–phonon coupling. Besides, O 1s and Co 1s x-ray absorption spectroscopy reveal that intercalated water condenses into a two-dimensional ice and showing no influence on a carrier doping.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
Na0.35CoO2·1.3H2O

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5Pressure not reportedunknown

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