Coupling of a high-energy excitation to superconducting quasiparticles in a cuprate from coherent charge fluctuation spectroscopy
Abstract
Dynamical information on spin degrees of freedom of proteins or solids can be obtained by NMR and electron spin resonance. A technique with similar versatility for charge degrees of freedom and their ultrafast correlations could move the understanding of systems like unconventional superconductors forward. By perturbing the superconducting state in a high-Tc cuprate, using a femtosecond laser pulse, we generate coherent oscillations of the Cooper pair condensate that can be described by an NMR/electron spin resonance formalism. The oscillations are detected by transient broad-band reflectivity and are found to resonate at the typical scale of Mott physics (2.6 eV), suggesting the existence of a nonretarded contribution to the pairing interaction, as in unconventional (non-Migdal-Eliashberg) theories.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- March 2013
- DOI:
- 10.1073/pnas.1218742110
- Bibcode:
- 2013PNAS..110.4539M