Gapped Nearly Free-Standing Graphene on an SiC(0001) Substrate Induced by Manganese Atoms

TL;DR

This study investigates how manganese atoms induce a transition in graphene on SiC(0001), transforming it into a nearly free-standing, semiconducting state with potential for device applications.

Contribution

It provides experimental evidence of manganese-induced decoupling of graphene from the substrate and a metal-to-insulator transition, revealing new ways to modify graphene's electronic properties.

Findings

Disappearance of conduction band upon manganese adsorption

Valence band maximum shifts below Fermi energy by 0.4 eV

Electronic correlations in graphene can be tuned by foreign atoms

Abstract

The electron band structure of manganese-adsorbed graphene on an SiC(0001) substrate has been studied using angle-resolved photoemission spectroscopy. Upon introducing manganese atoms, the conduction band of graphene completely disappears and the valence band maximum is observed at 0.4 eV below Fermi energy. At the same time, the slope of the valence band decreases, approaching the electron band structure calculated using the local density approximation method. While the former provides experimental evidence of the formation of nearly free-standing graphene on an SiC substrate, concomitant with a metal-to-insulator transition, the latter suggests that its electronic correlations can be modified by foreign atoms. These results pave the way for promising device applications using graphene that is semiconducting and charge neutral.