Multiple bosonic mode coupling in the charge dynamics of the electron-doped superconductor (Pr$_{2-x}$Ce$_x$)CuO$_4$

Schachinger, E.; Homes, C. C.; Lobo, R. P. S. M.; Carbotte, J. P.

Multiple bosonic mode coupling in the charge dynamics of the electron-doped superconductor (Pr$_{2-x}$Ce$_x$)CuO$_4$

Authors

Description

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 $τ^{-1}_{\rm op}(ω,T)$ 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 $\sim 10 $meV and a second one at $\sim 45 $meV. 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 towards higher energies with increasing temperatures. It also 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.
10 pages, 8 figures submitted to Physical Review B