We study the ionic Hubbard model in one dimension at zero temperature. As the Hubbard interaction is increased, the system is known to evolve from a band insulator to a Mott insulator. In order to examine the transition nature, we perform a cellular dynamical mean-field calculation with an exact diagonalization technique employed as an impurity solver. From the computed local density of states, we estimate the spectral gap as the interaction strength is varied. We also calculate the spectral weight, which exhibits characteristic features for different phases.
- Cellular dynamical mean-field theory
- Ionic hubbard model