Nonmonotonic dx2-y2 superconducting order parameter in Nd2-xCexCuO4 -: art. no. 107002

Low energy polarized electronic Raman scattering of the electron-doped superconductor Nd1-xCexCuO4 (x = 0.15, T-c = 22 K) has revealed a nonmonotonic d(x 2-y 2) superconducting order parameter. It has a maximum gap of 4.4k(B)T(c) at Fermi surface intersections with an anti ferromagnetic Brillouin zone (the hot spots) and a smaller gap of 3.3k(B)T(c) at fermionic Brillouin zone boundaries. The gap enhancement in the vicinity of the hot spots emphasizes the role of anti ferromagnetic fluctuations and the similarity in the origin of superconductivity for electron- and hole-doped cuprates.