Unadulterated spectral function of low-energy quasiparticles in Bi2Sr2CaCu2O8+δ

Fitting the momentum distribution photoemission spectra to the Voigt profile appears to be a robust procedure to purify the interaction effects from the experimental resolution. In application to Bi2Sr2CaCu2O8+delta high-T-c cuprates, the procedure reveals the true scattering rate at low binding energies and temperatures, and consequently, the true value of the elastic scattering. Reaching the minimal value similar to 16 meV, the elastic scattering does not reveal a systematic dependence on doping level, but is rather sensitive to impurity concentration and can be explained by the forward scattering on out-of-plane impurities. The inelastic scattering is found to form well-defined quasiparticles with the scattering rate similar to omega(2) and similar to omega(3), above and below T-c, respectively.