ARPES study of Pb doped Bi_2Sr_2CaCu_2O_8 - a new Fermi surface picture
  High resolution angle resolved photoemission data from Pb doped Bi_2Sr_2CaCu_2O_8 (Bi2212) with suppressed superstructure is presented. Improved resolution and very high momentum space sampling at various photon energies reveal the presence of two Fermi surface pieces. One has the hole-like topology, while the other one has its van Hove singularity very close to (pi,0), its topology at some photon energies resembles the electron-like piece. This result provides a unifying picture of the Fermi surface in the Bi2212 compound and reconciles the conflicting reports. 
P. V. Bogdanov, A. Lanzara, X. J. Zhou, S. A. Kellar, D. L. Feng, E.   D. Lu, J. -I. Shimoyama, K. Kishio, Z. Hussain, and Z...