Parametrization of Stillinger-Weber Potential Based on Valence Force Field Model: Application to Single-Layer MoS2 and Black Phosphorus

TL;DR

This paper introduces a method to derive Stillinger-Weber potentials from valence force field models, enabling accurate and stable molecular dynamics simulations for materials like MoS2 and black phosphorus.

Contribution

The authors develop an analytical parametrization approach that transfers valence force field accuracy to Stillinger-Weber potentials for covalent materials.

Findings

Accurate phonon spectra prediction for MoS2 and black phosphorus

Stable molecular dynamics simulations using the new potentials

Input scripts provided for simulation packages

Abstract

We propose to parametrize the Stillinger-Weber potential for covalent materials starting from the valence force field model. All geometrical parameters in the Stillinger-Weber potential are determined analytically according to the equilibrium condition for each individual potential term, while the energy parameters are derived from the valence force field model. This parametrization approach transfers the accuracy of the valence force field model to the Stillinger-Weber potential. Furthermore, the resulting Stilliinger-Weber potential supports for stable molecular dynamics simulations, as each potential term is at energy minimum state separately at the equilibrium configuration. We employ this procedure to parametrize Stillinger-Weber potentials for the single-layer MoS2 and black phosphorous. The obtained Stillinger-Weber potentials predict accurate phonon spectrum and mechanical behaviors. We also provide input scripts of these Stillinger-Weber potentials used by publicly available simulation packages including GULP and LAMMPS.