Unveiling the nature of the bosonic excitations that mediate the formation of Cooper pairs is a key issue for understanding unconventional superconductivity. A fundamen- tal step toward this goal would be to identify the relative weight of the electronic and phononic contributions to the overall frequency (\Omega) dependent bosonic function, \Pi(\Omega). We perform optical spectroscopy on Bi2212 crystals with simultaneous time- and frequency-resolution; this technique allows us to disentangle the electronic and phononic contributions by their different temporal evolution. The strength of the interaction ({\lambda}~1.1) with the electronic excitations and their spectral distribution fully account for the high critical temperature of the superconducting phase transition.
@article{arxiv.1203.0588,
title = {Disentangling the electronic and phononic glue in a high-Tc superconductor},
author = {Stefano Dal Conte and Claudio Giannetti and Giacomo Coslovich and Federico Cilento and Davide Bossini and Tadesse Abebaw and Franceco Banfi and Gabriele Ferrini and Hiroshi Eisaki and Martin Greven and Andrea Damascelli and Dirk van der Marel and F. Parmigiani},
journal= {arXiv preprint arXiv:1203.0588},
year = {2012}
}