Characteristics of oxygen isotope substitutions in the quasiparticle spectrum of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$

Abstract

There is an ongoing debate about the nature of the bosonic excitations responsible for the quasiparticle self energy in high temperature superconductors -- are they phonons or spin fluctuations? We present a careful analysis of the bosonic excitations as revealed by the `kink' feature at 70 meV in angle resolved photoemission data using Eliashberg theory for a d-wave superconductor. Starting from the assumption that nodal quasiparticles are not coupled to the $(\pi ,\pi )$ magnetic resonance, the sharp structure at $70$meV can be assigned to phonons. We find that not only can we account for the shifts of the kink energy seen on oxygen isotope substitution but also get a quantitative estimate of the fraction of the area under the electron-boson spectral density which is due to phonons. We conclude that for optimally doped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ phonons contribute $\sim 10$% and non-phononic excitations $\sim 90$%.

6 pages, 3 figures

References in corpus (14)

• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• Electronic Origin of the Inhomogeneous Pairing Interaction in the High-Tc Superconductor Bi2Sr2CaCu2O8+d
• High-energy kink in high-temperature superconductors
• Doping dependence of the coupling of electrons to bosonic modes in the single-layer high-temperature Bi2Sr2CuO6 superconductor
• An Isotopic Fingerprint of Electron-Phonon Coupling in High-Tc Cuprates
• Identification of a New Form of Electron Coupling in Bi2Sr2CaCu2O8 Superconductor by Laser-Based Angle-Resolved Photoemission
• On the Relation between Optical Conductivity and Quasiparticle Dynamics: Boson Structures
• Evidence for a pseudogap in underdoped $B{i}_{2}S{r}_{2}CaC{u}_2{O}_{8+\delta }$ and $YB{a}_{2}C{u}_3{O}_{6.50}$ from in-plane optical conductivity measurements
• Finite band inversion of ARPES in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ in comparison with optics
• Role of Inelastic Tunneling through the Barrier in Scanning Tunneling Microscope Experiments on Cuprates
• Multiple bosonic mode coupling in the charge dynamics of the electron-doped superconductor (Pr${}_{2-x}$Ce${}_x$)CuO${}_4$
• Optical Sum Rule in Finite Bands
• Absence of an isotope effect in the magnetic resonance in high-$T_c$ superconductors
• Optical sum in Nearly Antiferromagnetic Fermi Liquid Model