title: Abrupt transition in quasiparticle dynamics at optimal doping in a cuprate superconductor system.
abstract: We report time-resolved measurements of the photoinduced change in reflectivity, DeltaR, in the Bi2Sr2Ca(1-y)Dy(y)Cu2O8+delta (BSCCO) system of cuprate superconductors as a function of hole concentration. We find that the kinetics of quasiparticle decay and the sign of DeltaR both change abruptly where the superconducting transition temperature T(c) is maximal. These coincident changes suggest that a sharp transition in quasiparticle dynamics takes place precisely at optimal doping in the BSCCO system.
authors.affiliation: Physics Department, University of California, Berkeley, Berkeley, California, USA.
authors.forename: N
authors.initials: N
authors.lastname: Gedik
authors.forename: M
authors.initials: M
authors.lastname: Langner
authors.forename: M
authors.initials: M
authors.lastname: Langer
authors.forename: J
authors.initials: J
authors.lastname: Orenstein
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Abe
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ando