Orbital Orderings in Ferromagnetic Metallic Manganites

抄録

Orbital orderings in ferromagnetic metallic manganites are studied. We study a model which describes the perovskite manganites in the ferromagnetic metallic phase at absolute zero by the mean field theory and by the self-consistent second order perturbation theory. Although various orbital ordered states are obtained by the mean field theory as in the previous studies, we find that no orbital ordered states with two-sublattice structures are stable in the ferromagnetic metallic phase when we take proper account of the electron correlation effect.