  Using low-energy electron microscopy, we study Co intercalation under
graphene grown on Ir(111). Depending on the rotational domain of graphene on
which it is deposited, Co is found intercalated at different locations. While
intercalated Co is observed preferentially at the substrate step edges below
certain rotational domains, it is mostly found close to wrinkles below other
domains. These results indicate that curved regions (near substrate atomic
steps and wrinkles) of the graphene sheet facilitate Co intercalation and
suggest that the strength of the graphene/Ir interaction determines which
pathway is energetically more favorable.
