Role of electron-electron correlation in the valence states of YBa2Cu3O7: Low-energy excitations and Fermi surface - art. no. 020507

We have studied the role of on-site correlation in the low-energy excitatio ns of YBa2Cu3O7 in the normal state, calculating self-energies and spectral functions according to the three-body-scattering approach. The method allo ws to include all the details of realistic ab initio band-structure calcula tions and to augment them with the inclusion of electron-electron correlati ons, getting quasiparticle energies for one-particle removal. It is found t hat correlation effects modify the energy dispersion of hole quasiparticle states, both in the high and low binding energy region, and strongly modify the Fermi surface topology.