We study superconductivity in the two-dimensional 16-band d-p model extracted from a tight-binding fit to the band structure of LaFeAsO, using the random phase approximation. When the intraorbital repulsion U is larger than the interorbital one U′, an extended s -wave (s± -wave) pairing with sign reversal of order parameter is mediated by antiferromagnetic spin fluctuations, while when U< U′ another kind of s -wave (s++ -wave) pairing without sign reversal is mediated by ferro-orbital fluctuations. The s++ -wave pairing is enhanced due to the electron-phonon coupling and then can be expanded over the realistic parameter region with U> U′.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2010 2 23|
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