title: Absence of hole confinement in transition-metal oxides with orbital degeneracy.
abstract: We investigate the spectral properties of a hole moving in a two-dimensional Hubbard model for strongly correlated t(2g) electrons. Although superexchange interactions are Ising-like, a quasi-one-dimensional coherent hole motion arises due to effective three-site terms. This mechanism is fundamentally different from the hole motion via quantum fluctuations in the conventional spin model with SU(2) symmetry. The orbital model describes also propagation of a hole in some e(g) compounds, and we argue that orbital degeneracy alone does not lead to hole self-localization.
authors: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors: Maria
authors: M
authors: Daghofer
authors: Krzysztof
authors: K
authors: Wohlfeld
authors: Andrzej M
authors: AM
authors: Oleś
authors: Enrico
authors: E
authors: Arrigoni
authors: Peter
authors: P
authors: Horsch