Electronic properties of CuO ₂ -planes: A DMFT study

Abstract:

We study one-particle spectra and the electronic band-structure of a CuO ₂ -plane within the three-band Hubbard model. The Dynamical Mean-Field Theory (DMFT) is used to solve the many particle problem. The calculations show that the optical gap is given by excitations from the lower Hubbard band into the so called Zhang-Rice singlet band. The optical gap turns out to be considerably smaller than the bare charge transfer energy () for a typical set of parameters, which is in agreement with experiment. We also investigate the dependence of the shape of the Fermi surface on the different hopping parameters t CuO and t OO. A value t OO / t CuO >0 leads to a Fermi surface surrounding the M point.