Abstract
In a recent nodal direction angular-resolved photoemission spectroscopy (ARPES) study of the renormalized electronic dispersion curves in , small changes in the “kink” structure around 70 meV were observed on to substitution. Based on the Eliashberg equations generalized to include the -wave symmetry of the superconducting gap, we show that these results are incompatible with predominant coupling to a single oxygen-phonon mode. They can be understood in a model where a peak centered at comprising of only 10% of the total area under the electron-boson interaction spectral density obtained by a maximum entropy inversion of nodal direction of ARPES data, is assigned to phonons and shifted in energy by the 6% expected for oxygen isotope effect. The remaining background with 90% of the area comes from spin fluctuations. Based on a momentum-averaged electron-boson spectral density recovered from optical scattering-rate data, we study corresponding isotope shifts expected in the optical response.
1 More- Received 8 October 2009
DOI:https://doi.org/10.1103/PhysRevB.81.014519
©2010 American Physical Society