Structural and electronic properties of zigzag graphene nanoribbon decorated with copper cluster

Abstract

Using density functional theory, zigzag graphene nanoribbon (Z-GNR) saturated with hydrogen atoms decorated with copper clusters containing one, two and three copper atoms has been studied. It is shown that the cluster of copper, despite the number of copper atoms, tends to occupy the edge sites of Z-GNR. The quality and quantity of copper---carbon bonds, possible diffusion path and charge transfers are discussed in detail. It has been shown that in decorated Z-GNR with copper clusters, "d" and "s" orbital of copper joint with "p" orbital of carbon create a stable and strong bond. We show that copper in its individual form, transfers electrical charge to Z-GNR. In case of two and three copper atoms in a cluster, two different stable structures, stand and sleep-modes, are introduced. Based on number of copper atoms in a cluster and the modes that cluster stabilized on Z-GNR, the Fermi state in the decorated Z-GNR can shift to lower or higher energies. We also study the transformation from sleep to stand-mode and demonstrate that it is highly unlikely that any conversion happens at low temperatures.