  Based on first-principles calculations, we demonstrate that Co decorated
silicene can host a quantum anomalous Hall state. The exchange field induced by
the Co atoms combined with the strong spin orbit coupling of the silicene opens
a nontrivial band gap at the K-point. As compared to other transition metals,
Co decorated silicene is unique in this respect, since usually hybridization
and spin-polarization induced in the silicene suppress a quantum anomalous Hall
state.
