Laser pulse probe of the chirality of Cooper pairs

Abstract

The internal chirality of Cooper pairs is shown to modify strongly the response of a superconductor to the local heating by a laser beam. The suppression of the chiral order parameter inside the hot spot appears to induce the supercurrents flowing around the spot region. The chirality also affects the sequential stage of thermal quench developing according to the Kibble-Zurek scenario: besides the generation of vortex-antivortex pairs the quench facilitates the formation of superconducting domains with different chirality. These fingerprints of the chiral superconducting state can be probed by any experimental techniques sensitive to the local magnetic field. The supercurrents encircling the hot spot originate from the inhomogeneity of the state with the broken time-reversal symmetry, and their detection would provide a convenient alternative to the search for spontaneous edge currents sensitive to the boundary properties. Thus, the suggested setup can help to resolve the long-standing problem of unambiguous detection of type of pairing in ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$, which is considered a good candidate for chiral superconductivity.