Unconventional pairing originating from the disconnected Fermi surfaces of superconducting LaFeAsO1-xFx

Phys Rev Lett. 2008 Aug 22;101(8):087004. doi: 10.1103/PhysRevLett.101.087004. Epub 2008 Aug 22.


For a newly discovered iron-based high T_{c} superconductor LaFeAsO1-xFx, we have constructed a minimal model, where inclusion of all five Fe d bands is found to be necessary. The random-phase approximation is applied to the model to investigate the origin of superconductivity. We conclude that the multiple spin-fluctuation modes arising from the nesting across the disconnected Fermi surfaces realize an extended s-wave pairing, while d-wave pairing can also be another candidate.