Junctions with ferromagnetic contacts to probe the pairing symmetry of iron pnictide superconductors

Abstract

The quantum transport of junctions with an iron-based superconductor (SC) of antiphase s-wave pairing, sandwiched in between two ferromagnets, is studied by the use of an extended Blonder-Tinkham-Klapwijk approach. It is shown that due to novel interband interference in the SC, oscillations of not only reflection and transmission probabilities but also differential conductances with energy in both ferromagnetic and antiferromagnetic magnetization alignments exhibit conspicuously characteristic peak and dip behavior at two gap energies. More importantly, the behavior is found to be thoroughly different from those without antiphase s-wave pairing for the SC, which can be used to experimentally probe the antiphase s-wave pairing in iron-based SCs. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.