Anisotropic Interlayer Force Field for Group-VI Transition Metal Dichalcogenides

TL;DR

This paper introduces an anisotropic interlayer force field for group-VI transition metal dichalcogenides, enabling accurate large-scale simulations of their interlayer interactions, phonon spectra, and mechanical properties.

Contribution

The paper presents a new anisotropic interlayer force field specifically designed for group-VI TMDs, validated against DFT calculations, and transferable to various heterostructures.

Findings

Force field agrees well with DFT binding energy and sliding surfaces

Bulk moduli predictions align with previous DFT results

Phonon spectra highlight the importance of anisotropic interface treatment

Abstract

An anisotropic interlayer force field that describes the interlayer interactions in homogeneous and heterogeneous interfaces of group-VI transition metal dichalcogenides (MX2 where M = Mo, W and X = S, Se) is presented. The force field is benchmarked against density functional theory calculations for bilayer systems within the Heyd-Scuseria-Ernzerhof hybrid density functional approximation, augmented by a nonlocal many-body dispersion treatment of long-range correlation. The parametrization yields good agreement with reference calculations of binding energy curves and sliding potential energy surfaces. It is found to be transferable to TMD junctions outside the training set that contain the same atom types. Calculated bulk moduli agree with most previous dispersion corrected DFT predictions, which underestimate available experimental values. Calculated phonon spectra of the various junctions under consideration demonstrate the importance of appropriately treating the anisotropic nature of layered interfaces. Considering our previous parameterization for MoS2, the interlayer potential enables accurate and efficient large-scale simulations of the dynamical, tribological, and thermal transport properties of a large set of homogeneous and heterogeneous TMD interfaces.