Migration barriers for surface diffusion on a rigid lattice: challenges and solutions

TL;DR

This paper addresses the challenges in calculating migration barriers for surface diffusion in rigid lattice Kinetic Monte Carlo simulations and proposes a systematic tethering force method for face-centered and body-centered cubic metals.

Contribution

It introduces a reliable tethering force approach to systematically compute migration barriers for metal lattices, facilitating large-scale KMC simulations.

Findings

Developed barrier sets for Cu and Fe surfaces

Published barrier data for use in KMC simulations

Enhanced the efficiency of barrier calculations for large systems

Abstract

Atomistic rigid lattice Kinetic Monte Carlo is an efficient method for simulating nano-objects and surfaces at timescales much longer than those accessible by molecular dynamics. A laborious part of constructing any Kinetic Monte Carlo model is, however, to calculate all migration barriers that are needed to give the probabilities for any atom jump event to occur in the simulations. One of the common methods of barrier calculations is Nudged Elastic Band. The number of barriers needed to fully describe simulated systems is typically between hundreds of thousands and millions. Calculations of such a large number of barriers of various processes is far from trivial. In this paper, we will discuss the challenges arising during barriers calculations on a surface and present a systematic and reliable tethering force approach to construct a rigid lattice barrier parameterization of face-centred and body-centred cubic metal lattices. We have produced several different barrier sets for Cu and for Fe that can be used for KMC simulations of processes on arbitrarily rough surfaces. The sets are published as Data in Brief articles and available for the use.