Si Intercalation Beneath Epitaxial Graphene: Modulating Mott States at the SiC(0001) Interface

Abstract

Intercalation has proven to be a powerful tool for tailoring the electronic properties of freestanding graphene layers as well as for stabilizing the intercalated material in a two-dimensional configuration. This work examines Si intercalation of epitaxial graphene on SiC(0001) using three preparation methods. Dangling bond states at the interface were found to undergo a Mott-Hubbard metal-insulator transition as a result of a significant on-site repulsion. Comparing this heterostructure consisting of graphene and a Mott insulator with a similar system without graphene, reveals the screening ability of graphene's conduction electrons on the on-site repulsion. The system presented here can serve as a template for further research on Mott insulators with variable band gap.