Emergent Odd-frequency Superconductivity on the Edge of Pnictides

Despite the presumed constructive coexistence of extended s-wave superconductivity and spin density wave (SDW) in certain Fe-pnictides, experiments show signatures of enhanced superconductivity at defects in the SDW. This motivates the analysis of pairing channels, beyond extended s-wave, that can emerge as a consequence of spatial inhomogeneity in conjunction with the superconductivity and spin-rotational symmetry breaking. Using a two-orbital model, we investigate the hypothesis that defects can enhance unconventional odd-frequency pairing within this coexistence phase. As the simplest example, we studied possible unconventional pairings on the edge and showed that certain types of anomalous odd frequency correlations are enhanced at edges of pnictides in the coexistence phase of SDW and superconductivity. Our results show that emergence of such superconducting states could potentially explain the enhancement of superfluid density in the defects of SDW in pnictides.