Are we van der Waals ready?

TL;DR

This study evaluates various density-functional-theory-based methods for accurately modeling van der Waals interactions in layered solids, assessing their reliability for predicting geometries, elastic properties, and binding energies.

Contribution

It provides a comprehensive comparison of multiple van der Waals methods on diverse layered materials, highlighting their strengths and limitations.

Findings

Non-local van der Waals functionals show promising accuracy.

Some methods reliably predict equilibrium geometries.

Guidelines for future development of van der Waals functionals.

Abstract

We apply a range of density-functional-theory-based methods capable of describing van der Waals interactions to weakly bonded layered solids in order to investigate their accuracy for extended systems. The methods under investigation are the local density approximation, semi-empirical force fields, non-local van der Waals density functionals and the random-phase approximation. We investigate the equilibrium geometries, elastic constants and the binding energies of a large and diverse set of compounds and arrive at conclusions about the reliability of the different methods. The study also points to some directions of further development for the non-local van der Waals density functionals.