We investigated the ionic Hubbard model with mass imbalance in one dimension, using the density matrix renormalization group method. This model exhibits a band insulator phase and an antiferromagnetic one, both with a finite spin gap. We found that this quantum phase transition is continuous, unalike the previous mean-field theory result. The von Neumann block entropy is maximum at the critical points, a fact that we used to build the phase diagram.
Categories: cond-mat.str-el quant-ph