title: Coupled multiple-mode theory for s±pairing mechanism in iron based superconductors.
abstract: We investigate the interplay between the magnetic and the superconducting degrees of freedom in unconventional multi-band superconductors such as iron pnictides. For this purpose a dynamical mode-mode coupling theory is developed based on the coupled Bethe-Salpeter equations. In order to investigate the region of the phase diagram not too far from the tetracritical point where the magnetic spin density wave, (SDW) and superconducting (SC) transition temperatures coincide, we also construct a Ginzburg-Landau functional including both SC and SDW fluctuations in a critical region above the transition temperatures. The fluctuation corrections tend to suppress the magnetic transition, but in the superconducting channel the intraband and interband contribution of the fluctuations nearly compensate each other.
authors.affiliation: The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, I-34151 Trieste, Italy.
authors.forename: M N
authors.initials: MN
authors.lastname: Kiselev
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Germany.
authors.forename: D V
authors.initials: DV
authors.lastname: Efremov
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Germany.
authors.forename: S L
authors.initials: SL
authors.lastname: Drechsler
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Germany.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink
authors.affiliation: School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv, Israel.
authors.forename: K
authors.initials: K
authors.lastname: Kikoin