Doping dependence of an n-type cuprate superconductor investigated by angle-resolved photoemission spectroscopy -: art. no. 257001

We present an angle-resolved photoemission doping dependence study of the n-type cuprate superconductor Nd2-xCexCuO4+/-delta, from the half-filled Mott insulator to the T-c = 24 K superconductor. In Nd2CuO4, we reveal the charge-transfer band for the first time. As electrons are doped into the system, this feature's intensity decreases with the concomitant formation of near-E-F spectral weight. At low doping, the Fermi surface is an electron-pocket (with volume similar tox) centered at (pi, 0). Further doping leads to the creation of a new holelike Fermi surface (volume similar to1 + x) centered at (pi, pi). These findings shed light on the Mott gap, its doping evolution, as well as the anomalous transport properties of the n-type cuprates.