We use coherent pump-probe spectroscopy to measure the photoinduced reflectivity \DeltaR, and complex dielectric function, {\delta}\in, of the electron-doped cuprate superconductor Nd_{2-x}Ce_xCuO_{4+\delta} at a value of x near optimal doping, as a function of time, temperature, and laser fluence. We observe the onset of a negative \DeltaR at T=85 K, above the superconducting transition temperature, T_c, of 23 K, that exhibits a form of scaling consistent with critical fluctuations in the time domain. A positive \Delta R onsets at T_c that we associate with superconducting order. We find that the two signals are strongly coupled below T_c, in a manner that suggests a repulsive interaction between superconductivity and antiferromagnetic correlations.
@article{arxiv.1208.0960,
title = {Dynamical Interplay between Coexisting Orders in the Electron-Doped Cuprate Superconductor Nd_{2-x}Ce_xCuO_4},
author = {J. P. Hinton and J. D. Koralek and G. Yu and E. M. Motoyama and Y. M. Lu and A. Vishwanath and M. Greven and J. Orenstein},
journal= {arXiv preprint arXiv:1208.0960},
year = {2012}
}