Unadulterated spectral function of low energy quasiparticles: Bi-2212, nodal direction

TL;DR

This paper uses Voigt profile fitting of photoemission spectra to accurately determine the low-energy quasiparticle spectral function in Bi-2212, revealing impurity effects and scattering behaviors across different doping levels.

Contribution

It introduces a robust fitting method to extract true scattering rates from ARPES data, clarifying the nature of quasiparticles and impurity effects in high-Tc cuprates.

Findings

Elastic scattering is around 16 meV and depends on impurities, not doping.

Quasiparticles exhibit quadratic and cubic energy dependence above and below Tc.

Energy-temperature asymmetry of scattering rate is discussed.

Abstract

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.