Electronic properties of CuO2-planes: A DMFT study

We study one-particle spectra and the electronic band-structure of a CuO2-p lane within the three-band Hubbard model. The Dynamical Mean-Field Theory ( DMFT) is used to solve the many particle problem. The calculations show tha t the optical gap Delta(opt) is given by excitations from the lower Hubbard band into the so called Zhang-Rice singlet band. The optical gap Delta(opt ) turns out to be considerably smaller than the bare charge transfer energy Delta (Delta = epsilon(p) - epsilon(d)) for atypical set of parameters, wh ich is in agreement with experiment. We also investigate the dependence of the shape of the Fermi surface on the different hopping parameters t(CuO) a nd t(OO). A value t(OO)/t(CuO) > 0 leads to a Fermi surface surrounding the M point.