Density functional calculation of transition metal adatom adsorption on graphene

Abstract

The functionalization of graphene (a single graphite layer) by the addition oftransition metal atoms of Mn, Fe and Co to its surface has been investigatedcomputationally using density functional theory. In the calculation, the graphene surfacesupercell was constructed from a single layer of graphite (0001) surface separated byvertical vacuum layers 2 nm thick. We found that the center of the hexagonal ringformed by carbon from graphene is the most stable site for Mn, Fe, Co to stayafter optimization. The calculated spin-polarized band structures of the grapheneencapsulating the Mn adatom indicate that the conduction bands are modifiedand move down due to the coupling between the Mn atom and graphene. For Feadsorbed on the graphene surface, it is semi-half-metallic, and the spin polarizationP is found to be 100%. The system of Co adatom on graphene exhibits metallic electronicstructure due to the density of states (DOS) peak at the band center with both majorityand minority spins. Local density of states analyses indicate a larger promotion of 4selectrons into the 3d state in Fe and Co, resulting in lower local moments compared to anMn adatom on the graphite surface.