ARPES studies of cuprate Fermiology: Superconductivity, pseudogap and quasiparticle dynamics

Abstract

We present our angle-resolved photoemission spectroscopy (ARPES) studies of the cuprate high-temperature superconductors; these studies elucidate the relation between superconductivity and the pseudogap and highlight low-energy quasiparticle dynamics in the superconducting state. Our experiments suggest that the pseudogap and the superconducting gap represent distinct states that coexist below Tc. Studies of Bi-2212 demonstrate that the near-nodal and near-antinodal regions behave differently as a function of temperature and doping, implying that different orders dominate in different momentum-space regions. However, the ubiquity of sharp quasiparticles all around the Fermi surface in Bi-2212 indicates that superconductivity extends into the momentum-space region dominated by the pseudogap, revealing subtlety in this dichotomy. In Bi-2201, the temperature dependence of antinodal spectra reveals particle-hole asymmetry and anomalous spectral broadening, which may constrain the explanation for the pseudogap. Noting that electron-boson coupling is an important aspect of cuprate physics, we end the paper with a discussion of the multiple 'kinks' in the nodal dispersion. Understanding these will be useful in establishing which excitations are important for superconductivity. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.