Phase transitions in the Haldane-Hubbard model within coherent potential approximation

Within the coherent potential approximation we study the two-dimensional Haldane-Hubbard model, in which an interplay between topology and correlation effects is realized. The model essentially describes correlated electrons moving in a honeycomb lattice with zero net magnetic flux. The influence of the next-nearest-neighbor hopping and electron correlations on the metal-insulator transitions are investigated by monitoring the density of states at the Fermi level and the energy gap. The topological properties of the insulators is determined by the Chern number. With a given next-nearest-neighbor hopping, electron correlations drive the system from the topological Chern insulator to a metal, and then to the topologically trivial Mott insulator.