Insulating behavior with spin and charge order in the ionic Hubbard model

Paramagnetic solutions of the ionic Hubbard model at half-filling in dimensions D>2 indicate that the band and the Mott insulator phases are separated by a metallic phase. We present zero-temperature dynamical mean-field theory solutions, which include antiferromagnetic long-range order and show that the one-particle spectral functions always possess an energy gap, and therefore the system is insulating for all interaction strengths. The staggered charge-density modulation coexists with antiferromagnetic long-range order of Neel type.