0−πphase shifts in Josephson junctions as a signature for thes±-wave pairing state

Abstract

We investigate Josephson junctions with superconducting ferropnictides, both in the diffusive and ballistic limit. We focus on the proposed ${s}_{\ifmmode\pm\else\textpm\fi{}}$-wave state and find that the relative phase shift intrinsic to the ${s}_{\ifmmode\pm\else\textpm\fi{}}$-wave state may provide $0\text{\ensuremath{-}}\ensuremath{\pi}$ oscillations in the Josephson current. This feature can be used to discriminate this pairing state from the conventional $s$-wave symmetry. The $0\text{\ensuremath{-}}\ensuremath{\pi}$ oscillations appear both as a function of the ratio of the interface resistances for each band and, more importantly, as a function of temperature, which greatly aids in their detection.