Anti-ferromagnetism enables electron-phonon coupling in iron-based superconductors

We show that a generic form of an anti-ferromagnetic wavefunction opens strong electron-phonon coupling channels in the iron-based superconductors. In the non-magnetic state these channels exist locally on a single iron atom, but are cancelled out between two iron atoms in the primitive unit cell. Our findings are mostly based on symmetry and are relevant for any iron-based superconductor. This work was supported by NSF Grant No. DMR15-1508412 and the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Computational resources have been provided by the DOE at Lawrence Berkeley National Laboratory's NERSC facility.