  Here, we demonstrate two reliable routes for the fabrication of armchair-edge
graphene nanoribbons (GNRs) on TbAu2/Au(111), belonging to a class of
two-dimensional ferromagnetic rare earth-gold intermetallic compounds.
On-surface synthesis directly on TbAu2 leads to the formation of GNRs, which
are short and interconnected with each other. In contrast, the intercalation
approach - on-surface synthesis of GNRs directly on Au(111) followed by rare
earth intercalation - yields GNRs on TbAu2/Au(111), where both the ribbons and
TbAu2 are of high quality comparable with those directly grown on clean
Au(111). Besides, the as-grown ribbons retain the same band gap while changing
from p-doping to weak n-doping mainly due to a change in the work function of
the substrate after the rare earth intercalation. The intercalation approach
might also be employed to fabricate other types of GNRs on various rare earth
intermetallic compounds, providing platforms to tailor the electronic and
magnetic properties of GNRs on magnetic substrates.
