Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 16: Superconductivity: Properties and Electronic Structure II
TT 16.8: Vortrag
Dienstag, 18. März 2025, 11:30–11:45, H32
Dynamics of non-thermal states in a cuprate superconductor revealed by mid-infrared three-pulse spectroscopy — •Angela Montanaro1,2,3, Enrico Maria Rigoni1,2, Giacomo Jarc1,2, Viktor Kabanov4, and Daniele Fausti1,2,3 — 1University of Trieste, 34127 Trieste, Italy — 2Elettra Sincrotrone Trieste, 34127 Trieste, Italy — 3University of Erlangen-Nürnberg, 91058 Erlangen, Germany — 4Jožef Stefan Institute, 1000 Ljubljana, 25123 Brescia, Italy
Unconventional cuprate superconductors exhibit anomalous high-frequency electrodynamics compared to standard BCS systems. In BCS superconductors, spectral weight redistribution occurs only near the superconducting gap energy, but in cuprates, changes extend to energies two orders of magnitude higher. This implies that high-energy electronic excitations might influence the pairing mechanism.
In this work, we disentangle the effects of high- and low-photon energy excitations in a prototype cuprate system. We set up a technique which combines two pump pulses having substantially different photon energy: a visible pulse much more energetic than the superconducting gap and a mid-infrared pump with photon energy smaller than the gap. Our findings show that the two photoexcitations have a different effect on the condensate electrodynamics. Moreover, we found that the overall response of the system strongly depends on the time-order of the two photoexcitations. This allowed us to constrain the lifetime of photoinjected carriers and ultimately the recovery time of the condensate.
Keywords: Ultrafast pump-probe spectroscopy; Superconductivity; Dynamical phase transitions; Quantum many-body systems; Photoinduced effects