Optimally doped cuprate are characterized by the presence of superconducting fluctuations in a relatively large temperature region above the critical transition temperature. We reveal here that the effect of thermal disorder, which decreases the condensate phase coherence at equilibrium, can be dynamically contrasted by photoexcitation with ultrashort midinfrared pulses. In particular, our findings reveal that light pulses with photon energy comparable to the amplitude of the superconducting gap and polarized in plane along the copper-copper direction can dynamically enhance the optical response associated with the onset of superconductivity. We propose that this effect can be rationalized by an effective d-wave BCS model, which reveals that midinfrared pulses result in a transient increase of the phase coherence.
Bibliographical noteFunding Information:
This research was undertaken thanks in part to funding from the Max Planck-UBC-UTokyo Centre for Quantum Materials and the Canada First Research Excellence Fund, Quantum Materials and Future Technologies Program. The work at UBC was supported by the Killam, Alfred P. Sloan, and Natural Sciences and Engineering Research Council of Canada’s (NSERC’S) Steacie Memorial Fellowships (A. D.), the Alexander von Humboldt Fellowship (A. D.), the Canada Research Chairs Program (A. D.), NSERC, Canada Foundation for Innovation (CFI) and CIFAR Quantum Materials Program. The work at the University of Minnesota was funded by the Department of Energy through the University of Minnesota Center for Quantum Materials under DE-SC-0016371. This research was mainly supported by the Italian Ministry of Education (MIUR), through Grant No. RBSI14ZIY2, financed under the Scientific Independence of Young Researchers program (SIR2014).
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