Laser pulse probe of chirality of Cooper pairs

TL;DR

This paper proposes a laser-based method to detect the chirality of Cooper pairs in superconductors by observing induced supercurrents and domain formation, aiding the identification of chiral superconductivity in materials like Sr2RuO4.

Contribution

It introduces a novel experimental approach using laser heating to probe the internal chirality of Cooper pairs and detect chiral superconducting states.

Findings

Laser heating induces supercurrents around hot spots in chiral superconductors.

Chirality influences vortex-antivortex pair formation during thermal quench.

Detection of supercurrents can reveal the presence of chiral order without boundary current measurements.

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 affects also 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 of the 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 Sr2RuO4 considered as a good candidate for chiral superconductivity.