Fermi surface features and Charge segregation in Bi2212 superconductor

Experiments are enlightening that the high T-c superconductivity in cuprate perovskites takes place in a particular phase showing segregation of localized and itinerant charge carriers. We have studied topological features of the Fermi surface of Bi2Sr2CaCu2O8+d (Bi2212) superconductor to investigate implication of charge segregation in the system. For the purpose we have used constant initial state angle-scanning photoemission supported by the energy distribution curves. The resulting Fermi surface measured over an extended Brillouin zone shows broken segments with partial gaps around (pi,0) and shadow bands around (0.5 pi,0.5 pi) and equivalent locations. In addition data provide an evidence for new electronic states at the Fermi surface due to a one dimensional band with a small dispersion and small k(F) along the (pi,0) direction. We argue that the depression of photointensity around (pi,0) and equivalent locations with well-defined k(F) and one dimensional band are related with charge ordering in the CuO2 plane along the (-pi, pi) direction and spin fluctuations along the (pi,0) direction.