Disorder-induced currents as signatures of chiral superconductivity

Chiral superconductors are expected to carry a spontaneous, chiral and perpetual current along the sample edge. However, despite availability of several candidate materials, such has not been observed in experiments. In this article, we suggest an alternative probe form impurity-induced currents. We first demonstrate that single non-magnetic impurity induces encircling current. Its direction depends on chirality order parameter sign potential. Building observation, consider case multiple impurities, e.g., realized as adatoms deposited surface superconductor. contrast response is obtained two cases: (a) when impurities all identical (b) have mixed positive negative signs. The former leads coherent currents within sample, arising from fusion individual loops. latter produces loops random lead incoherent local These scenarios can be distinguished by measuring induced magnetic field using recent probes diamond NV centres. argue may easier observe than edge currents, they tuned varying strength concentration. these results toy model for $p_x \pm i p_y$ superconductivity square lattice. develop improved scheme Bogoliubov deGennes (BdG) simulations where both well determined self-consistently.