Multiple bosonic mode coupling in the charge dynamics of the electron-doped superconductor (Pr(2-x)Ce(x))CuO(4)

We analyze optical spectroscopy data of the electron-doped superconductor (Pr(2-x)Ce(x))CuO(4) (PCCO) to investigate the coupling of the charge carriers to bosonic modes. The method of analysis is the inversion of the optical scattering rate tau(-1)(op)(omega,T) at different temperatures T by means of maximum entropy technique combined with Eliashberg theory. We find that in the superconducting state the charge carriers couple to two dominant modes, one at similar to 12 meV and a second one at similar to 45 meV as well as to a high energy background. The low energy mode shows a strong temperature dependence and disappears at or slightly above the critical temperature T(c). The high energy mode exists above T(c) and moves toward higher energies with increasing temperatures. It becomes less prominent at temperatures >100 K above which it evolves into a typical spin-fluctuation background. In contrast to the hole-doped high-T(c) superconductors PCCO proves to be a superconductor close to the dirty limit.