2025/11/28 by Karuzin, Daniil K., Skvortsov, Mikhail A. · 1 citation
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2511.23431
openalex publication_date 2025/11/28 · openalex created_date 2025/12/03 · openalex updated_date 2026/07/28
We develop a theory for the plasmon spectrum in dirty superconductors across the entire temperature range. Starting with the microscopic Keldysh sigma model description, we link the plasmon dispersion ω(q) to the optical conductivity σ(ω,T) of a superconductor, which requires analytical continuation to the lower half-plane of complex frequency. This approach reveals a discontinuity at the superconducting transition: a jump in both the real and imaginary parts of ω(q) at Tc. For any temperature below Tc, the plasmon dispersion terminates at a critical wave vector qc(T) where plasmons remains undamped, with weakly T-dependent ω[qc(T)] ≈ 2Δ(0). Plasmons significantly attenuate only within a narrow 5% temperature window near Tc, with the propagating mode recovering at large q.