Kinetic Activation-Relaxation Technique and Self-Evolving Atomistic Kinetic Monte Carlo: Comparison of on-the-fly kinetic Monte Carlo algorithms

TL;DR

This paper compares two on-the-fly kinetic Monte Carlo methods, k-ART and SEAKMC, highlighting their similarities, differences, and respective advantages in simulating materials science problems with large and complex systems.

Contribution

It provides a detailed comparison of k-ART and SEAKMC, demonstrating their agreement and contrasting their flexibility and speed in different simulation scenarios.

Findings

k-ART and SEAKMC produce similar results for vacancy and interstitial loop simulations.

k-ART offers more flexible geometry handling, including amorphous systems.

SEAKMC achieves faster simulations through active volume localization.

Abstract

We present a comparison of the kinetic Activation-Relaxation Technique (k-ART) and the Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC), two off-lattice, on-the-fly kinetic Monte Carlo (KMC) techniques that were recently used to solve several materials science problems. We show that if the initial displacements are localized the dimer method and the Activation-Relaxation Technique \emph{nouveau} provide similar performance. We also show that k-ART and SEAKMC, although based on different approximations, are in agreement with each other, as demonstrated by the examples of 50 vacancies in a 1950-atom Fe box and of interstitial loops in 16000-atom boxes. Generally speaking, k-ART's treatment of geometry and flickers is more flexible, e.g. it can handle amorphous systems, and rigorous than SEAKMC's, while the later's concept of active volumes permits a significant speedup of simulations for the systems under consideration and therefore allows investigations of processes requiring large systems that are not accessible if not localizing calculations.