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Ferromagnetism in the two dimensional t-t' Hubbard model at the Van Hove density

R. Hlubina·S. Sorella·F. Guinea
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Abstract

Using an improved version of the projection quantum Monte Carlo technique, we study the square-lattice Hubbard model with nearest-neighbor hopping t and next-nearest-neighbor hopping t', by simulation of lattices with up to 20 X 20 sites. For a given R=2t'/t, we consider that filling which leads to a singular density of states of the noninteracting problem. For repulsive interactions, we find an itinerant ferromagnet (antiferromagnet) for R=0.94 (R=0.2). This is consistent with the prediction of the T-matrix approximation, which sums the most singular set of diagrams.

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R. Hlubina, S. Sorella, F. Guinea. 1996-09-26. Ferromagnetism in the two dimensional t-t' Hubbard model at the Van Hove density. https://doi.org/10.1103/physrevlett.78.1343

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