Many-body dispersion interactions using Wannier functions with an application to 2D materials.*

Accurate determination of dispersive interactions is an essential prerequisite for characterizing structure, stability, and function in materials with chemically inert components. Currently, practical implementations of calculating van der Waals energies from first principles rely on many-body dispersion methods and the development of nonlocal functionals based on the random phase approximation. In this work, we offer a new implementation of a many-body dispersion interactions based on a Wannier function framework. Using an interpolation scheme that maps density functional theory electronic structure to a description based on Maximally Localized Wannier Functions, the atoms in the materials are represented via Wannier Function spreads and centers. Rather than using isotropic atomic dipoles as done in previous methods, our approach utilizes the macroscopic optical response which takes into account the underlying electronic structure and optical anisotropy of the materials. Our method provides the foundation to discern the role of anisotropy and beyond dipolar correlations for an efficient and improved description of vdW interactions in layered materials.