Van der Waals bonding in layered compounds from advanced first-principles calculations

TL;DR

This study uses advanced first-principles calculations to quantify van der Waals interactions in layered compounds, revealing a universal interlayer binding energy around 20 meV/Ų that explains their exfoliation into two-dimensional materials.

Contribution

It provides the first comprehensive quantitative analysis of interlayer van der Waals energies across many layered compounds using advanced computational methods.

Findings

Interlayer binding energies are approximately 20 meV/Ų for most layered materials.

The universal energy value explains the ease of exfoliating layered compounds into 2D materials.

Advanced first-principles methods effectively quantify weak van der Waals interactions.

Abstract

Although the precise microscopic knowledge of van der Waals interactions is crucial for understanding bonding in weakly bonded layered compounds, very little quantitative information on the strength of interlayer interaction in these materials is available, either from experiments or simulations. Here, using many-body perturbation and advanced density-functional theory techniques, we calculate the interlayer binding and exfoliation energies for a large number of layered compounds and show that, independent of the electronic structure of the material, the energies for most systems are around 20 meV/\AA$^2$. This universality explains the successful exfoliation of a wide class of layered materials to produce two-dimensional systems, and furthers our understanding the properties of layered compounds in general.