Fast general two- and three-body interatomic potential

TL;DR

This paper presents a new machine learning interatomic potential, GTTP, which is as fast as empirical potentials, highly flexible, and capable of accurately modeling complex quantum interactions for large atomic systems.

Contribution

The paper introduces GTTP, a fast, flexible, and accurate machine learning interatomic potential that remains computationally constant regardless of the number of parameters.

Findings

GTTP is as fast as traditional empirical potentials.

GTTP outperforms common empirical potentials in large system simulations.

GTTP is transferable across different atomic system sizes and types.

Abstract

We introduce a new class of machine learning interatomic potentials - fast General Two- and Three-body Potential (GTTP), which is as fast as conventional empirical potentials and require computational time that remains constant with increasing fitting flexibility. GTTP does not contain any assumptions about the functional form of two- and three-body interactions. These interactions can be modeled arbitrarily accurately, potentially by thousands of parameters not affecting resulting computational cost. Time complexity is O(1) per every considered pair or triple of atoms. The fitting procedure is reduced to simple linear regression on ab initio calculated energies and forces and leads to effective two- and three-body potential, reproducing quantum many-body interactions as accurately as possible. Our potential can be made continuously differentiable any number of times at the expense of increased computational time. We made a number of performance tests on one-, two- and three-component systems. The flexibility of the introduced approach makes the potential transferable in terms of size and type of atomic systems. We show that trained on randomly generated structures with just 8 atoms in the unit cell, it significantly outperforms common empirical interatomic potentials in the study of large systems, such as grain boundaries in polycrystalline materials.