  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 one 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
