Signature of the nonmonotonic d -wave gap in electron-doped cuprates

We address the issue whether the data on optical conductivity and Raman scattering in electron-doped cuprates below Tc support the idea that the d -wave gap in these materials is nonmonotonic along the Fermi surface. We calculate the conductivity and Raman intensity for elastic scattering and find that a nonmonotonic gap gives rise to several specific features in optical and Raman response functions. We argue that all these features are present in the experimental data on Nd2-x Cex Cu O4 and Pr2-x Cex Cu O4 compounds.