title: Momentum and energy dependence of the anomalous high-energy dispersion in the electronic structure of high temperature superconductors.
abstract: Using high-resolution angle-resolved photoemission spectroscopy we have studied the momentum and photon energy dependence of the anomalous high-energy dispersion, termed waterfalls, between the Fermi level and 1 eV binding energy in several high-T_{c} superconductors. We observe strong changes of the dispersion between different Brillouin zones and a strong dependence on the photon energy around 75 eV, which we associate with the resonant photoemission at the Cu3p-->3d_{x;{2}-y;{2}} edge. We conclude that the high-energy "waterfall" dispersion results from a strong suppression of the photoemission intensity at the center of the Brillouin zone due to matrix element effects and is, therefore, not an intrinsic feature of the spectral function. This indicates that the new high-energy scale in the electronic structure of cuprates derived from the waterfall-like dispersion may be incorrect.
authors.affiliation: Institute for Solid State Research, IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany.
authors.forename: D S
authors.initials: DS
authors.lastname: Inosov
authors.forename: J
authors.initials: J
authors.lastname: Fink
authors.forename: A A
authors.initials: AA
authors.lastname: Kordyuk
authors.forename: S V
authors.initials: SV
authors.lastname: Borisenko
authors.forename: V B
authors.initials: VB
authors.lastname: Zabolotnyy
authors.forename: R
authors.initials: R
authors.lastname: Schuster
authors.forename: M
authors.initials: M
authors.lastname: Knupfer
authors.forename: B
authors.initials: B
authors.lastname: Büchner
authors.forename: R
authors.initials: R
authors.lastname: Follath
authors.forename: H A
authors.initials: HA
authors.lastname: Dürr
authors.forename: W
authors.initials: W
authors.lastname: Eberhardt
authors.forename: V
authors.initials: V
authors.lastname: Hinkov
authors.forename: B
authors.initials: B
authors.lastname: Keimer
authors.forename: H
authors.initials: H
authors.lastname: Berger