  We perform a theoretical study of the effects of electronic correlations on
the superconducting gap structure of multi-band superconductors. In particular,
by comparing standard RPA-based spin-fluctuation mediated gap structures to
those obtained within the FLEX formalism for an iron-based superconductor, we
obtain directly the feedback effects from electron-electron interactions on the
momentum-space gap structure. We show how self-energy effects can lead to an
orbital inversion of the orbital-resolved spin susceptibility, and thereby
invert the hierarchy of the most important orbitals channels for
superconducting pairing. This effect has important consequences for the
detailed gap variations on the Fermi surface. We expect such self-energy
feedback on the pairing gap to be generally relevant for superconductivity in
strongly correlated multi-orbital systems.
