LARGE-U HUBBARD-MODEL - THE CROSSOVER FROM ONE DIMENSION TO 2 DIMENSIONS

The anisotropic two-dimensional (2D) large-U Hubbard model as an assem bly of parallel chains has been studied. Based on the analytical under standing of the Hubbard chain, the charge and spin separation is shown to persist into 2D and the holon is turned into a semion by attaching a half-quantized flux. The confinement of holon and spinon will block interchain coherent hopping of single holons and the coherent interch ain motion is found to originate from the pair hoppings of holons. The mean-field states of the semionic Hamiltonian for holons and the impl ication for the isotropic 2D case are discussed.