Spectral Evidence For Bogoliubov Quasiparticle In Triple-Layered High-T-C Superconductor Bi2sr2ca2cu3o10

The superconducting quasiparticle predicted by BCS theory is investigated in a triple-layered high-T-c cuprate Bi2Sr2Ca2Cu3O10+delta, by angle-resolved photoemission spectroscopy (ARPES). We have succeeded in observing the quasiparticle dispersion below and above the Fermi level, and performed a quantitative analysis based on BCS theory. The excellent agreement in the energy dispersion and the coherence factors between the ARPES experiment and BCS theory indicates the basic validity of BCS formalism in describing the superconducting state of cuprates. (C) 2004 Elsevier B.V. All rights reserved.