We analyze doping dependent spectral intensities and Fermi surface maps obtained recently in Nd$_{ 2-x}$Ce$_x$CuO$_{ 4\pm\delta}$ (NCCO) via high resolution ARPES measurements, and show that the behavior of this electron-doped compound can be understood as the closing of a Mott (pseudo) gap, leading to a quantum critical point just above optimal doping. The doping dependence of the effective Hubbard $U$ adduced by comparing theoretical and experimental spectra is in resonable accord with various estimates and a simple screening calculation.
Categories: cond-mat.supr-con