Transition to an Insulating Phase Induced by Attractive Interactions in   the Disordered Three-Dimensional Hubbard Model
  We study numerically the interplay of disorder and attractive interactions for spin-1/2 fermions in the three-dimensional Hubbard model. The results obtained by projector quantum Monte Carlo simulations show that at moderate disorder, increasing the attractive interaction leads to a transition from delocalized superconducting states to the insulating phase of localized pairs. This transition takes place well within the metallic phase of the single-particle Anderson model. 
Bhargavi Srinivasan, Giuliano Benenti and Dima L. Shepelyansky   (Toulouse / Como)