Ordered states in the disordered Hubbard model
  The Hubbard model is studied in which disorder is introduced by putting the on-site interaction to zero on a fraction f of (impurity) sites of a square lattice. Using Quantum Monte Carlo methods and Dynamical Mean Field theory we find that antiferromagnetic long-range order is initially enhanced at half-filling and stabilized off half-filling by the disorder. The Mott-Hubbard charge gap of the pure system is broken up into two pieces by the disorder: one incompressible state remains at average density n=1 and another can be seen slightly below n=1+f. Qualitative explanations are provided. 
P. J. H. Denteneer (1), M. Ulmke (2), R. T. Scalettar (3), and G. T.   Zimanyi (3) ((1) Leiden University, (2) Universitat A...