An Electronic Structure Perspective of Sliding of Graphene on SiC

We investigate sliding of the top-most layer of few-layer graphene (FLG) systems with layer thicknesses from n=1 to n=4 on 4H-SiC{0001} surfaces using density functional theory. We examine the frictional properties through energy profiles and changes in barrier heights with respect to sliding directions, number of layers and surface termination both for sliding at a fixed height and sliding under external normal force. The relation between electronic structures and friction mechanisms; as well as the dependence of the electronic properties of FLG on SiC on stacking order, substrate charge transfer and applied load, are discussed via a thorough examination of the changes in the band structures and charge densities during sliding.