Possible phase-sensitive tests of pairing symmetry in pnictide superconductors

The discovery of the new class of pnictide superconductors has engendered a controversy about their pairing symmetry, with proposals ranging from an extended s wave or "s±" symmetry to nodal or nodeless d-wave symmetry to still more exotic order parameters such as p wave. In this Letter, building on the earlier, similar work performed for the cuprates, we propose several phase-sensitive Josephson interferometry experiments, each of which may allow resolution of the issue.