  Using dynamical mean-field theory and exact diagonalization we study the
phase diagram of the repulsive Haldane-Hubbard model, varying the interaction
strength and the sublattice potential difference. In addition to the quantum
Hall phase with Chern number $C=2$ and the band insulator with $C=0$ present
already in the noninteracting model, the system also exhibits a $C=0$ Mott
insulating phase, and a $C=1$ quantum Hall phase. We explain the latter phase
by a spontaneous symmetry breaking where one of the spin-components is in the
Hall state and the other in the band insulating state.
