Orbital coupling and superconductivity in the iron pnictides

We demonstrate that strong interorbital interaction is very efficient to achieve superconductivity due to magnetic fluctuations in the iron pnictides. Fermi-surface states that are coupled by the antiferromagnetic wave vector are often of different orbital nature, causing pair-hopping interactions between distinct Fe-3d orbitals to become important. Performing a self-consistent fluctuation exchange calculation below Tc we determine the superconducting order parameter as function of intra- and interorbital couplings. We find an s± -pairing state with Tc 80 K for realistic parameters.