Ferromagnetism at the edges of the stacked graphitic fragments: an ab initio study

We carry out first-principles density functional calculations to investigate electronic and magnetic structures of the stacked graphitic fragments. Ferromagnetically ordered ground states are found to be stable in the zigzag edges of an isolated graphene, regardless of whether or not the edges are passivated with hydrogen atoms. However, the localized moments in the hydrogen-terminated edge vanish upon stacking the graphite fragments. Interlayer and inter-edge interactions are investigated in detail, and it is found that dangling bonds are indispensable to the formation of the ferromagnetism at the edges of the stacked graphitic fragments. (C) 2004 Elsevier B.V. All rights reserved.