Modified pairing structure due to momentum-dependent correlations in iron-based superconductors*

We discuss the influence of momentum-dependent correlation effects arising from particle-hole interactions on the superconducting gap structure of iron-based superconductors. Within the Eliashberg formalism, we obtain a modified linearized gap equation arising from the spin-fluctuation interaction in the weak-coupling regime which includes self-consistent renormalizations of quasiparticle weights. The modification of the particle-particle interaction vertex by particle-hole processes modifies the superconducting gap structure, i.e. momentum-dependent enhancement or suppression of gap amplitude compared to traditional spin-fluctuation pairing calculations. We obtain good agreement with experimentally observed anisotropic gap structures in LiFeAs, indicating that inclusion of non-local correlation effects in the existing weak-coupling theories can account for observed signatures of the correlated iron-based superconductors.