Microwave Kerr/Faraday Resonance in Two-dimensional Chiral Superconductors

In this presentation, we discuss the polar Kerr and Faraday effects in two-dimensional multiband chiral superconductors. We show that clapping modes—relative-phase and amplitude oscillations between the two chiral components of the superconducting order parameter—generate Kerr and Faraday signals in the microwave regime. In thin films of chiral superconductors, the Kerr and Faraday rotation angles exhibit resonant enhancements with sign reversals when the probe frequency matches the clapping-mode energies, reaching peak magnitudes on the order of 100 nrad—well within current experimental sensitivity. These resonances are accessible in superconducting atomic-layer materials and provide a generic probe of chiral superconductivity in two dimensions.