- Accepted Paper
Effect of superconducting fluctuations on nonreciprocal dichroism and gyrotropy
Phys. Rev. B - Accepted 28 September, 2026
DOI: https://doi.org/10.1103/ffpb-133j
Phys. Rev. B - Accepted 28 September, 2026
DOI: https://doi.org/10.1103/ffpb-133j
We study the spatially dispersive conductivity of a two-dimensional noncentrosymmetric superconductor, demonstrating that it acquires a nonreciprocal, odd-in-wavevector component from fluctuation-induced Cooper pairs above the critical temperature . Utilizing time-dependent Ginzburg-Landau theory generalized to include particle-hole asymmetry and the cubic Lifshitz invariant of trigonal superconductors, we compute the Aslamazov-Larkin contribution to the gyrotropic conductivity in closed form, including its complete frequency dependence. The dissipative part describes nonreciprocal directional dichroism: it is odd in frequency and displays a nonmonotonic dependence, peaking at frequencies comparable to the decay rate of fluctuating Cooper pairs. Its Kramers-Kronig dual component describes gyrotropic birefringence, which remains finite in the static limit and is strongly enhanced as the temperature approaches , as long as the probe frequency stays below the pair decay rate. Both effects require simultaneously broken inversion and time-reversal symmetries, are dependent on particle-hole asymmetry in close analogy to the fluctuation Hall effect, and trace to the same asymmetric Cooper-pair dispersion responsible for the superconducting diode effect and the giant magnetochiral anisotropy observed near . In this regime this critical enhancement dominates over the smooth normal-state gyrotropy, which we evaluate for the same band model as a baseline. Finally, we frame our analysis within the context of gated transition metal dichalcogenides like MoS, discussing the implications for probing superconducting dynamics through nitrogen-vacancy-center quantum noise spectroscopy.
If the author has provided any supplemental materials with this article they will be available upon publication of the version of record.