Unadulterated spectral function of low energy quasiparticles: Bi-2212,   nodal direction
  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 Bi-2212 high-Tc 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 ~ 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 quadratic and cubic energy dependence of the scattering rate above and below Tc, respectively. The observed energy-temperature asymmetry of the scattering rate is also discussed. 
D. V. Evtushinsky, A. A. Kordyuk, S. V. Borisenko, V. B. Zabolotnyy,   M. Knupfer, J. Fink, B. Buechner, A. V. Pan, A. Erb, ...