Evaluation of van der Waals density functionals for layered materials

TL;DR

This paper evaluates modern van der Waals density functionals for layered materials, demonstrating that recent models like FIA theory provide near-quantitative predictions and are promising for nanomaterial research.

Contribution

The study introduces and assesses new vdW dispersion models, especially FIA theory, showing their improved accuracy over previous methods for layered materials.

Findings

FIA theory offers close to quantitative predictions.

Modern vdW methods like D3 and optB88vdW perform well with some exceptions.

We are nearing the capability to reliably model vdW forces in layered materials.

Abstract

In 2012, Bjorkman et al. posed the question "Are we van der Waals ready?" [J. Phys.: Condens. Matter, 2012, 24, 424218] about the ability of ab initio modelling to reproduce van der Waals (vdW) dispersion forces in layered materials. The answer at that time was no, however. Here we report on a new generation of vdW dispersion models and show that one, fractionally-ionic atom (FIA) theory, offers close to quantitative predictions for layered structures. Furthermore, it does so from a qualitatively correct picture of dispersion forces. Other methods, such as D3 and optB88vdW also work well, albeit with some exceptions. We thus argue that we are nearly vdW ready, and that some modern dispersion methods are accurate enough to be used for nanomaterial prediction, albeit with some caution required.