Fast & accurate interatomic potentials for describing thermal vibrations

Abstract

© 2020 The Authors Molecular dynamics (MD) is a powerful technique that can be used to study thermal vibrations/phonons and properly account for their role in different phenomena that are important in mechanical engineering, chemistry, physics and materials science. However, despite the widespread usage of MD to study various phenomena, direct comparisons between experiments and simulations are often associated with low fidelity, due to the inaccuracy of the interatomic potentials (IAPs) employed. This issue has become the main barrier to utilizing MD for studying phenomena that depend on or involve atomic vibrations, and subsequently deriving physically meaningful insights. Towards solving this problem, we present a new approach to making IAPs that are specifically optimized to accurately describe thermal vibrations/phonons. The approach enables nearly exact reproduction of ab initio phonon dispersion relations (i.e., < 1%) error), accurate forces and thermal conductivity (i.e., <5% and <10% error respectively), and low computational expense like that of traditional IAPs.