  The topological Haldane model (THM) on a honeycomb lattice is a prototype of
systems hosting topological phases of matter without external fields. It is the
simplest model exhibiting the quantum Hall effect without Landau levels, which
motivated theoretical and experimental explorations of topological insulators
and superconductors. Despite its simplicity, its realization in condensed
matter systems has been elusive due to a seemingly difficult condition of
spinless fermions with sublattice-dependent magnetic flux terms. While there
have been theoretical proposals including elaborate atomic-scale engineering,
identifying candidate THM materials has not been successful, and the first
experimental realization was recently made in ultracold atoms. Here we suggest
that a series of Fe-based honeycomb ferromagnetic insulators, AFe2(PO4)2
(A=Ba,Cs,K,La) possess Chern bands described by the THM. How to detect the
quantum anomalous Hall effect is also discussed.
