Ferromagnetic fluctuation and superconductivity in Na0.35CoO2·1.3H2O:FLEX study ofmulti-orbital Hubbardmodel
نویسندگان
چکیده
Spin and charge fluctuations and superconductivity in Na0.35CoO2·1.3H2O are studied based on a multi-orbital Hubbard model. By applying the fluctuation exchange (FLEX) approximation, we show that the Hund’s-rule coupling between the Co t2g orbitals causes ferromagnetic spin fluctuation. Triplet pairing is favored by this ferromagnetic fluctuation on the hole-pocket band. We propose that, in Na0.35CoO2·1.3H2O, Co t2g orbitals and inter-orbital Hund’s-rule coupling play important roles on the triplet pairing, and this compound can be a first example of the triplet superconductor mediated by inter-orbital-interaction-induced ferromagnetic fluctuation.
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