2026/07/16 by Andrei Muratov, А.Ы. Муратов, Yevgeny Rakhmanov +5
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Superconductivity in MgB2 and Alloys
paper · pdf · doi:10.1007/s10948-026-07222-8
With infrared Fourier-transform spectroscopy and spectroscopic ellipsometry we investigated the in-plane reflectance of the superconducting Na0.27K0.27Rb0.27Fe1.7Se2 single crystals with a critical temperature Tc≈ 34.3 K over a broad frequency range at temperatures of 4--300 K. The normal-state response of Na0.27K0.27Rb0.27Fe1.7Se2 is analyzed by a Drude-Lorentz model with one Drude component. The temperature dependences of the plasma frequency, optical conductivity, scattering rate, and dc resistivity of the Drude component in the normal state are presented. We report a Fano-shaped mode at 1430~cm-1 indicating a coupling of the discrete mode presumably related to some electronic transition to a two-magnon continuum as well as a low-frequency broad band assigned to the acoustic magnon branch of the antiferromagnetic superstructure. These features persist in the reflectance in both the normal and superconducting states suggesting a mesoscopic coexistence of superconductivity and magnetism in Na0.27K0.27Rb0.27Fe1.7Se2.