(a) Typical structure geometry of a Fe atom on top of the hollow position of a 4 × 4 supercell of graphene. (b) Bulk band structure with SOC included along the high symmetry lines. The Fermi level is exactly located in the gap. (c) and (d) Zoom-in plots of the band structure at K and K′ points, respectively. Gaps of ∼5.5 meV, circled by the green dotted curves, are opened. (e) and (f) Berry curvature distribution Ω of the valence bands near K and K′ points. The Berry curvatures at K and K′ share the same sign, thus giving a nonzero Chern number. Reprinted with permission from Ref. [12]. Copyright 2010 by the American Physical Society.