A non-equilibrium approach to study the electron-boson coupling in cuprate superconductors

Abstract

We report time and frequency resolved reflectivity measurements on an Y-substituted optimally-doped Bi2212 crystal at T=300 K. We exploit the Extended Drude formalism generally used to describe the equilibrium optical response of the high temperature superconductors (HTSC) to develop a differential model to interpolate the pump-induced modification of the reflectivity over the entire energy range set by the spectral content of the probe. The spectra at different delay times are satisfactorily reproduced by the differential model in term of a transient variation of the electronic and bosonic temperatures. This new approach paves the way to disentangle the bosonic contribution of different origin to the glue function ∏(Ω) and to draw important conclusion about the unknow pairing mechanism in cuprate superconductors.