0-$\pi$ phase shifts in Josephson junctions as a signature for the $s_{\pm}$-wave pairing state

TL;DR

This paper explores how 0-$$-$$ oscillations in Josephson junctions with ferropnictide superconductors can serve as signatures of the $s_$-wave pairing state, aiding in distinguishing it from conventional s-wave symmetry.

Contribution

It demonstrates that the intrinsic phase shift in the $s_$-wave state causes observable 0-$$-$$ oscillations in Josephson currents, which depend on interface resistance ratios and temperature.

Findings

0-$$-$$ oscillations are predicted in Josephson currents.

Oscillations depend on interface resistance ratios for each band.

Temperature variation enhances the detectability of these oscillations.

Abstract

We investigate Josephson junctions with superconducting ferropnictides, both in the diffusive and ballistic limit. We focus on the proposed $s_\pm$-wave state, and find that the relative phase shift intrinsic to the $s_\pm$-wave state may provide 0-$\pi$ oscillations in the Josephson current. This feature can be used to discriminate this pairing state from the conventional s-wave symmetry. The 0-$\pi$ 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.