  By means of exact diagonalizations, the Bernevig-Hughes-Zhang model at
quarter-filling in the limit of strong Hubbard on-site repulsion is
investigated. We find that the non-interacting metallic state will be turned
into a Chern insulator with saturated magnetization under strong correlations.
That is, at such a metal-insulator transition, both the topological and the
magnetic properties of the system are changed due to spontaneous breaking of
time reversal symmetry in the ground states. According to our findings, this
topological phase transition seems to be of first order. Our results illustrate
the interesting physics in topological Mott transitions and provide guidance to
the search of more interaction-induced topological phases in similar systems.

Strongly Correlated Electrons