The one-dimensional asymmetric Hubbard model at partial band filling

We study the one-dimensional asymmetric Hubbard model (AHM) through the White's density matrix renormalization group technique at the density n=0.8. The AHM describes a correlated system where the hopping of electrons depend on their spin. The spin structure factor and the charge structure factor of heavy electrons were calculated as a function of the hopping and the repulsive on-site interaction. We found that the ground state displays phase separation for strong coupling, and a non-universal critical hopping separates the states of density wave and the phase separation. This outcome generalizes the result found one in the Falicov-Kimball model, which is a particular case of the AHM