Noble metals induced magnetic properties of graphene

The adsorption energies, stable configurations, electronic structures, and magnetic properties of the graphene with noble metal (NM=Pt, Ag, and Au) atom adsorption were investigated using first-principles density-functional theory. It is found that the bridge site is the most stable adsorption site for the Pt adatom; the Ag adatom can be stabilized almost equally at the bridge or the top site, while the Au adatom prefers to be adsorbed at top site. The Pt-graphene interaction is stronger than the interaction of Ag-graphene and Au-graphene, since the Pt atom has an unsaturated electronic d-shell (d9s1). While there is no net magnetic moment for the Pt adatom, the Ag and Au adatoms still exhibit magnetic character on the graphene. The magnetic moments of the NM–graphene systems may be quenched (e.g., Pt–graphene), reduced (e.g., Ag–graphene) or not changed (e.g., Au–graphene) as compared with the values before adsorption. Therefore, the magnetic character of the adatom–graphene system can be turned by adsorbing different NM atoms on the graphene.

► In this paper, we find that the noble metal (NM) atoms with different electronic configurations (e.g., those with or without unsaturated d shells) exhibit different electronic and magnetic properties on graphene.
► Magnetic moment of a NM atom may be quenched (e.g., Pt), reduced (e.g., Ag) or not changed (e.g., Au).
► Magnetic character of the adatom–graphene system can thus be turned by adsorbing different NM atoms on the graphene.
► Control of spin-polarized electronic structure and magnetic properties in the adatom–graphene systems may find potential applications in the graphene-based electronic and spintronic devices.