Dispersive and Covalent Interactions Between Graphene and Metal Surfaces from the Random Phase Approximation

TL;DR

This paper employs the Random Phase Approximation to accurately compute the potential energy surfaces of graphene adsorbed on various metal surfaces, revealing a delicate balance between covalent and dispersive interactions.

Contribution

It demonstrates that RPA effectively captures both van der Waals and covalent interactions in graphene-metal adsorption, surpassing common approximation methods.

Findings

Adsorption involves a competition between chemisorption and physisorption minima.

RPA provides a more accurate description of the interaction energies.

Both covalent and dispersive forces are equally important in these systems.

Abstract

We calculate the potential energy surfaces for graphene adsorbed on Cu(111), Ni(111), and Co(0001) using density functional theory and the Random Phase Approximation (RPA). For these adsorption systems covalent and dispersive interactions are equally important and while commonly used approximations for exchange-correlation functionals give inadequate descriptions of either van der Waals or chemical bonds, RPA accounts accurately for both. It is found that the adsorption is a delicate competition between a weak chemisorption minimum close to the surface and a physisorption minimum further from the surface.