A single-band Hubbard model with nearest and next-nearest neighbor hopping is studied for d = 1, 2, 3, using both analytical and numerical techniques. In one dimension, saturated ferromagnetism is found above a critical value of U for a band structure with two minima and for small and intermediate densities. This is an extension of a scenario recently proposed by Muller-Hartmann. For three dimensions and nonpathological band structures, it is proven that such a scenario does not work.
Low density ferromagnetism in the Hubbard model
PIERI, Pierbiagio;
1996-01-01
Abstract
A single-band Hubbard model with nearest and next-nearest neighbor hopping is studied for d = 1, 2, 3, using both analytical and numerical techniques. In one dimension, saturated ferromagnetism is found above a critical value of U for a band structure with two minima and for small and intermediate densities. This is an extension of a scenario recently proposed by Muller-Hartmann. For three dimensions and nonpathological band structures, it is proven that such a scenario does not work.File in questo prodotto:
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