Berlin 2024 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 50: Superconductivity: Theory II

TT 50.3: Talk

Wednesday, March 20, 2024, 15:30–15:45, H 3005

Non-equilibrium THz response of time-reversal symmetry breaking superconductors — •Silvia Neri and Dirk Manske — Max Planck Institute for Solid State Research D-70569, Stuttgart, Germany

Time-reversal symmetry breaking (TRSB) superconductors are unconventional superconductors that show a rich collective mode spectra. These collective excitations in superconductors provide crucial information of the symmetry broken phase, in particular, serving as a fingerprint for determining the ground state gap symmetry. In this work we consider multiple TRSB superconductors characterized by an order parameter of the form Δ = Δ₁ + iΔ₂. We provide a classification scheme of the collective excitations in the above systems as a function of the ratio between the components Δ₁ / Δ₂. In order to excite the many modes in the systems we have adopted two different probes: a quench symmetry of the condensate and a finite momentum transfer induced by an external electric field. Both methods allow us to excite and identify the different modes in the spectra. Furthermore, we have numerically simulated the response resulting from an excitation scheme mimicking a pump-prob experimental scenario. We have calculated the transient optical response identifying and classifying the resulting spectra also in terms of the component ratio. Our classification could provide a way to distinguish between different order parameters symmetries of a TRSB superconducting condensate and estimate the magnitude of the different components constituting the sample.

Keywords: Time-reversal symmetry breaking superconductors; collective excitations; Non-equilibrium; pump-probe