Phase separation in the Hubbard model using the dynamical cluster approximation

Phase separation in the Hubbard model is investigated with the dynamical cluster approximation. We find that it is present in the paramagnetic solution for values of filling smaller than 1 and at finite temperature when a positive next-nearest-neighbor hopping is considered. The phase-separated region is characterized by a mixture of a strongly correlated metallic and Mott insulating phases. Our results indicate that phase separation is driven by the formation of doped regions with strong antiferromagnetic correlations and low kinetic energy.