Graphene on metals: a Van der Waals density functional study

TL;DR

This study employs a van der Waals density functional within DFT to accurately analyze graphene's weak adsorption on various metal surfaces, revealing minimal impact on graphene's electronic structure and contrasting with previous LDA predictions.

Contribution

It introduces the use of vdW-DF in DFT to study graphene-metal interactions, showing weak binding and negligible electronic structure changes, improving understanding of graphene's substrate effects.

Findings

vdW-DF predicts weak binding energies for graphene on all studied metals.

Graphene-metal distances are in the range 3.40-3.72 Å.

Graphene's bandstructure remains largely unaffected by metal substrates.

Abstract

We use density functional theory (DFT) with a recently developed van der Waals density functional (vdW-DF) to study the adsorption of graphene on Al, Cu, Ag, Au, Pt, Pd, Co and Ni(111) surfaces. In constrast to the local density approximation (LDA) which predicts relatively strong binding for Ni,Co and Pd, the vdW-DF predicts weak binding for all metals and metal-graphene distances in the range 3.40-3.72 \AA. At these distances the graphene bandstructure as calculated with DFT and the many-body G$_0$W$_0$ method is basically unaffected by the substrate, in particular there is no opening of a band gap at the $K$-point.