Abstract
Using an improved version of the projection quantum Monte Carlo technique, we study the square-lattice Hubbard model with nearest-neighbor hopping and next-nearest-neighbor hopping by simulation of lattices with up to sites. For a given , 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 ( ). This is consistent with the prediction of the -matrix approximation, which sums the most singular set of diagrams.
- Received 17 May 1996
DOI:https://doi.org/10.1103/PhysRevLett.78.1343
©1997 American Physical Society