Armitage N P, Ronning F, Lu D H, Kim C, Damascelli A, Shen K M, Feng D L, Eisaki H, Shen Z-X, Mang P K, Kaneko N, Greven M, Onose Y, Taguchi Y, Tokura Y
Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2002 Jun 24;88(25 Pt 1):257001. doi: 10.1103/PhysRevLett.88.257001. Epub 2002 Jun 5.
We present an angle-resolved photoemission doping dependence study of the n-type cuprate superconductor Nd(2-x)Ce(x)CuO(4+/-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 approximately x) centered at (pi,0). Further doping leads to the creation of a new holelike Fermi surface (volume approximately 1+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.
我们展示了对n型铜酸盐超导体Nd(2 - x)Ce(x)CuO(4±δ)从半填充莫特绝缘体到Tc = 24 K超导体的角分辨光电子能谱掺杂依赖性研究。在Nd2CuO4中,我们首次揭示了电荷转移带。当电子被掺杂到系统中时,这一特征的强度随着近费米能谱权重的同时形成而降低。在低掺杂时,费米面是以(π,0)为中心的电子口袋(体积约为x)。进一步掺杂会导致在(π,π)处形成一个新的类空穴费米面(体积约为1 + x)。这些发现揭示了莫特能隙、其掺杂演变以及n型铜酸盐的反常输运性质。