FERMI-SURFACE AND ELECTRONIC-STRUCTURE OF ND2-XCEXCUO4-DELTA

Using angle-resolved photoemission, we have mapped out the Fermi surface (FS) of single crystal Nd2-xCexCuO4-delta when doped as a superconductor (x = 0.15) and overdoped as a metal (x = 0.22). The measured FS agrees very well with local-density-approximation calculations and appears to shift with electron doping as expected by a band-filling scenario. The observed FS shape suggests that a model Hamiltonian with only nearest-neighbor interactions is not sufficient to describe the electronic structure near E(F); next-nearest-neighbor interactions should also be considered.