title: Sharp low-energy feature in single-particle spectra due to forward scattering in d-wave cuprate superconductors.
abstract: There is an enormous interest in the renormalization of the quasiparticle (qp) dispersion relation of cuprate superconductors both below and above the critical temperature T_{c} because it enables the determination of the fluctuation spectrum to which the qp's are coupled. A remarkable discovery by angle-resolved photoemission spectroscopy (ARPES) is a sharp low-energy feature (LEF) in qp spectra well below the superconducting energy gap but with its energy increasing in proportion to T_{c} and its intensity increasing sharply below T_{c}. This unexpected feature needs to be reconciled with d-wave superconductivity. Here, we present a quantitative analysis of ARPES data from Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} (Bi2212) using Eliashberg equations to show that the qp scattering rate due to the forward scattering impurities far from the Cu-O planes is modified by the energy gap below T_{c} and shows up as the LEF. This is also a necessary step to analyze ARPES data to reveal the spectrum of fluctuations promoting superconductivity.
authors.affiliation: Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea.
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Hong
authors.affiliation: Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea.
authors.forename: Jin Mo
authors.initials: JM
authors.lastname: Bok
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhang
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: He
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhou
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Varma
authors.affiliation: Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea and Asia Pacific Center for Theoretical Physics, Pohang 790-784, Korea.
authors.forename: Han-Yong
authors.initials: HY
authors.lastname: Choi