Domain Wall in a Chiral p-Wave Superconductor: A Pathway for Electrical Current

Superconductors with p(x) +/- ip(y) pairing symmetry are characterized by chiral edge states, but these are difficult to detect in equilibrium since the resulting magnetic field is screened by the Meissner effect. Nonequilibrium detection is hindered by the fact that the edge excitations are Majorana fermions, which cannot transport charge near the Fermi level. Here we show that the boundary between p(x) + ip(y) and p(x) - ip(y) domains forms a one-way channel for electrical charge. We derive a product rule for the domain wall conductance, which allows us to cancel the effect of a tunnel barrier between metal electrodes and the superconductor and provides a unique signature of topological superconductors in the chiral p-wave symmetry class.