Charge displacement induced by intercalation of graphite-like nanoclusters in amorphous carbon with copper

Interaction of an impurity Cu atom with carbon in copper-intercalated graphite-like nanoclusters in a-C:H has been considered in a simple tight-binding approximation. Clusters with simple configurations were used to show that partial ionization of Cu gives rise to metallization of a semiconductor cluster and to a substantial charge redistribution in the latter. The presence of copper initiates in the cluster internal polarization with components directed both normal to the graphene-fragment plane and parallel to it. The lowering of the cluster symmetry induced by copper intercalation activates the Raman band G in the IR spectrum of a-C:H.