A scenario for the electronic state in the manganase perovskites: the orbital correlated metal

Abstract

We argue that, at low temperatures and well into the ferromagnetic phase, the physics of the manganase perovskites may be characterized by a correlated metallic state near a metal insulator transition where the orbital degrees of freedom play a main role. This follows from the observation that a two-band degenerate Hubbard model under a strong magnetic field can be mapped onto a para-orbital single band model. We solve the model numerically using the quantum Monte Carlo technique within a dynamical mean field theory which is exact in the limit of large lattice connectivity. We argue that the proposed scenario may allow for the qualitative interpretation of a variety of experiments which were also observed in other (early) transition metal oxides.