Doping and Temperature Dependence of the Mass Enhancement Observed in the CuprateBi2Sr2CaCu2O8+δ

Abstract
High-resolution photoemission is used to study the electronic structure of the cuprate superconductor, Bi2Sr2CaCu2O8+δ, as a function of hole doping and temperature. A kink observed in the band dispersion in the nodal line in the superconducting state is associated with coupling to a resonant mode observed in neutron scattering. From the measured real part of the self-energy it is possible to extract a coupling constant which is largest in the underdoped regime, then decreasing continuously into the overdoped regime.