title: Coexistence of two sharp-mode couplings and their unusual momentum dependence in the superconducting state of Bi2Sr2CaCu2O(8+δ) revealed by laser-based angle-resolved photoemission.
abstract: High-resolution laser-based angle-resolved photoemission measurements have been carried out on Bi2Sr2CaCu2O(8+δ) (Bi2212) superconductors to investigate momentum dependence of electron coupling with collective excitations (modes). Two coexisting energy scales are clearly revealed over a large momentum space for the first time in the superconducting state of the overdoped Bi2212 superconductor. These two energy scales exhibit distinct momentum dependence: one keeps its energy near 78 meV over a large momentum space while the other changes its energy from ∼40  meV near the antinodal region to ∼70  meV near the nodal region. These observations provide a new picture on momentum evolution of electron-boson coupling in Bi2212 that electrons are coupled with two sharp modes simultaneously over a large momentum space in the superconducting states. Their unusual momentum dependence poses a challenge to our current understanding of electron-mode-coupling and its role for high-temperature superconductivity in cuprate superconductors.
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, 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 100080, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhang
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 100080, China.
authors.forename: Daixiang
authors.initials: D
authors.lastname: Mou
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Peng
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Shaolong
authors.initials: S
authors.lastname: He
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Dong
authors.affiliation: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Wen
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Xu
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Gu
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Qinjun
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Shenjin
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Chuangtian
authors.initials: C
authors.lastname: Chen
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Zuyan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Choi
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: National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhou