| We study the interplay of itinerant fermions and localized magnetic moments on the frustrated checkerboard lattice at half filling. Even weak electronic kinetic energy lifts the macroscopic degeneracy of the magnetic ground state and selects a magnetic "flux"-phase, whose low-energy bands are given by graphene-like Dirac fermions. For weaker magnetic interactions, the Dirac fermions acquire a topologically nontrivial mass and a quantum anomalous Hall (QAH) state emerges. Itinerant electrons coupled to frustrated localized spin thus turn out to provide a realization of Haldane's proposal of a QAH state for graphene. |
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