Stability, electronic, and magnetic behaviors of Cu adsorbed graphene: A first-principles study

Stable configurations, electronic structures, and magnetic behaviors for Cu single atom and dimer adsorption on graphene have been investigated by first-principles calculations, using both gradient generalized approximation (GGA) and GGA+U methods. It is found that Cu single atom, sitting above a carbon atom, is the most stable configuration, while the most stable configuration for Cu dimer is perpendicular to the graphene plane above the bridge site. In both calculations, magnetic moments were detected in Cu single-atom-adsorbed graphene, which is mainly caused by the unsaturated s-electrons of the Cu atom. No magnetic moment was observed in Cu dimer-adsorbed graphene in both cases, but a band gap was observed in the GGA+U calculation, while a metallic system was observed in the GGA calculation. This demonstrates that the electronic structure of graphene can be modified via Cu adsorption. The Cu dimer, sitting parallel to the graphene plane above the C atoms, offers the possibility for the formation of Cu atom chain or wire on graphene, which might have potential nanoelectronic applications.