Volume 86, Number 6, June 2009
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||30 June 2009|
Characteristics of oxygen isotope substitutions in the quasiparticle spectrum of Bi2Sr2CaCu2O8+
Institute of Theoretical and Computational Physics, Graz University of Technology - A-8010 Graz, Austria, EU
2 Department of Physics and Astronomy, McMaster University - Hamilton, Ontario N1G 2W1, Canada
3 The Canadian Institute for Advanced Research - Toronto, Ontario M5G 1Z8, Canada
Corresponding author: Schachinger@itp.tu-graz.ac.at
Accepted: 9 June 2009
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 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 Bi2Sr2CaCu2O8+ phonons contribute ~ 10% and non-phononic excitations ~ 90%.
PACS: 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 74.25.Kc – Phonons / 74.72.Hs – Bi-based cuprates
© EPLA, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.