Comment on: Nonmonotonic $d_{x^2-y^2}$ Superconducting Order Parameter in Nd${}_{2-x}$Ce${}_x$CuO${}_4$

F. Venturini, R. Hackl, U. Michelucci

In a recent letter Blumberg and collaborators claim that a non-monotonic $d_{x^2-y^2}$ form for the superconducting order parameter is required to explain their Raman scattering me…