%0 Journal Article
%T Constrained-path quantum Monte Carlo simulations of the zero-temperature disordered two-dimensional Hubbard model
%A M. Enjalran
%A F. Hebert
%A G. G. Batrouni
%A R. T. Scalettar
%A Shiwei Zhang
%J Physics
%D 2001
%I arXiv
%R 10.1103/PhysRevB.64.184402
%X We study the effects of disorder on long-range antiferromagnetic correlations in the half-filled, two dimensional, repulsive Hubbard model at T=0. A mean field approach is first employed to gain a qualitative picture of the physics and to guide our choice for a trial wave function in a constrained path quantum Monte Carlo (CPQMC) method that allows for a more accurate treatment of correlations. Within the mean field calculation, we observe both Anderson and Mott insulating antiferromagnetic phases. There are transitions to a paramagnet only for relatively weak coupling, U < 2t in the case of bond disorder, and U < 4t in the case of on-site disorder. Using ground-state CPQMC we demonstrate that this mean field approach significantly overestimates magnetic order. For U=4t, we find a critical bond disorder of Vc = (1.6 +- 0.4)t even though within mean field theory no paramagnetic phase is found for this value of the interaction. In the site disordered case, we find a critical disorder of Vc = (5.0 +- 0.5)t at U=4t.
%U http://arxiv.org/abs/cond-mat/0102172v2