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

TL;DR

This study explores silicon intercalation beneath epitaxial graphene on SiC(0001), demonstrating a Mott-Hubbard transition and the screening effects of graphene's conduction electrons, offering a platform for Mott insulator research.

Contribution

It introduces a novel Si intercalation method that modulates Mott states at the graphene/SiC interface, revealing the impact of graphene's conduction electrons on electron correlations.

Findings

Dangling bond states undergo a Mott-Hubbard transition.

Graphene screens the on-site electron repulsion.

System serves as a template for Mott insulator studies.

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.