Electronic transport in copper-graphene composites

Abstract

We investigate electronic transport properties of copper-graphene (Cu-G) composites using a density-functional theory (DFT) framework. Conduction in composites is studied by varying the interfacial distance of copper/graphene/copper (Cu/G/Cu) interface models. Electronic conductivity of the models computed using the Kubo-Greenwood formula shows that the conductivity increases with decreasing Cu-G distance and saturates below a threshold Cu-G distance. The DFT-based Bader charge analysis indicates increasing charge transfer between Cu atoms at the interfacial layers and the graphene with decreasing Cu-G distance. The electronic density of states reveals increasing contributions from both copper and carbon atoms near the Fermi level with decreasing Cu-G interfacial distance. By computing the space-projected conductivity of the Cu/G/Cu models, we show that the graphene forms a bridge to the electronic conduction at small Cu-G distances, thereby enhancing the conductivity.