A new approach for perovskites in large dimensions

Using the Hubbard Hamiltonian for transition metal-3d and oxygen-2p states with perovskite geometry, we propose a new scaling procedure for a nontrivial extension of these systems to large spatial dimensions $D$. The scaling procedure is based on a selective treatment of different hopping processes for large $D$ and can not be generated by a unique scaling of the hopping element. The model is solved in the limit $D \rightarrow \infty$ by the iterated perturbation theory and using an extended non-crossing approximation. We discuss the evolution of quasi particles at the Fermi-level upon doping, leading to interesting insight into the dynamical character of the charge carriers near the metal insulator instability of transition metal oxide systems, three dimensional perovskites and other strongly correlated transition metal oxides.