Anisotropic interlayer force fields for van der Waals interfaces: Development and applications

The anisotropic nature of layered materials is key to many of their unique physical properties. The design and control of novel layered architectures requires a microscopic understanding of their intra- and inter-layer interactions. Ab initio simulations, based on, e.g., density functional theory, often provide valuable insights regarding their structural, mechanical, dynamical, and electronic properties. However, such calculations are often computationally demanding, thus limiting the treatment to relatively small length and time scales. Classical molecular dynamic simulations, based on physically motivated force-fields, may offer a viable computationally efficient alternative, when parameterized appropriately against ab initio reference data for small model systems. The general strategy usually relies on a separate treatment of intra- and inter-layer interactions. When considering the latter, popular isotropic potentials, such as those presented by Lennard-Jones and Morse, often fail to simultaneously capture binding and sliding physics. Therefore, anisotropic interlayer force fields, based on the Kolmogorov-Crespi scheme, have become the tool-of-choice. In this review, we summarize progress in the field of anisotropic interlayer force field, including the fundamental theoretical framework, parameterization, and representative applications to selected physical properties. We also discuss potential directions for further advancement, based on state-of-the-art developments in simulation technologies.