  It is shown that a generic form of an antiferromagnetic wave function opens
strong electron-phonon coupling channels in the iron-based superconductors. In
the nonmagnetic state these channels exist locally on a single iron atom, but
are canceled out between the two iron atoms in the primitive unit cell. Our
findings are based on symmetry and the presence of an xz/yz Fermi surface near
the M point and thus should be relevant for the known iron-based pnictide or
chalcogenide superconductors.
