Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 93: Superconductivity – Poster II
TT 93.12: Poster
Thursday, March 12, 2026, 18:00–20:00, P4
Fluxon mass in superconductors probed by circularly polarized terahertz radiation — •Roman Tesař1, Michal Šindler1, Pavel Lipavský2, Christelle Kadlec1, and Jan Koláček1 — 1Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic — 2Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
We employ an original method for detecting magnetic circular dichroism in YBCO thin films using FIR/THz laser radiation. The observed dichroism is clearly related to Abrikosov vortices (fluxons). Differential transmission of left- and right-handed circular polarization arises in the superconducting state under an applied magnetic field, but vanishes at zero magnetic field and in the normal state. Fluxon dynamics can be understood within a theoretical model that incorporates the fluxon mass, the equation of fluxon motion, and the interaction with circularly polarized light. The electric field drives a supercurrent that deflects fluxons via the Magnus effect perpendicular to the current flow. The resulting cyclotron motion of fluxons affects the supercurrent and thus the transmittance. We measured circular dichroism as a function of magnetic field and temperature at several laser frequencies for two YBCO samples with distinct doping. A good agreement with theoretical predictions allowed us to estimate the effective mass of a fluxon. Nevertheless, the fluxon mass still remains somewhat controversial and not fully resolved. The presented experimental technique is also applicable for the investigation of cyclotron resonance in semiconductors and magnon modes in magnetic materials.
Keywords: mass of Abrikosov vortex; high-temperature superconductor; magnetic circular dichroism; terahertz radiation