Graphene decoupling through oxygen intercalation on Gr/Co and Gr/Co/Ir interfaces

TL;DR

This study uses density functional theory to show how oxygen intercalation can decouple graphene from Co and Ir substrates, restoring its electronic properties and enabling tunable surface characteristics.

Contribution

It provides detailed insights into how oxygen intercalation modifies the structural and electronic interactions at Gr/Co and Gr/Co/Ir interfaces, revealing a method to control graphene's properties.

Findings

Oxygen increases graphene-Co distance in both interfaces.

Oxygen intercalation reduces hybridization, restoring graphene's Dirac cone.

Theoretical results agree with experimental photoemission data.

Abstract

We perform a density functional theory study of the effects of oxygen adsorption on the structural and electronic properties of Gr/Co(0001) and Gr/Co/Ir(111) interfaces. In both interfaces, the graphene-Co distance increases with increasing O concentration. The oxygen intercalation effectively decreases the electronic interaction, preventing the hybridization of graphene states with Co $d$-orbitals, hence (partly) restoring the typical Dirac cone of pristine graphene. In the case of graphene/Co 1ML/Ir(111), which presents a moir\'e pattern, the interplay between the O distribution and the continuous change of the graphene-Co registry can be used to tune graphene corrugation and electronic properties. The computed electronic properties are in very good agreement with previously reported angle resolved photoemission spectroscopy and photoemission electron microscopy measurements for Gr/Co(0001).