Tungsten migration energy barriers for surface diffusion: a parameterization for KMC simulations

TL;DR

This paper provides a comprehensive parameterization of tungsten surface diffusion barriers for Kinetic Monte Carlo simulations, enabling accurate modeling of rough surfaces and nanostructures.

Contribution

It introduces a detailed set of migration energy barriers for tungsten surface diffusion, including multiple neighbor processes, validated through KMC and Molecular Dynamics comparisons.

Findings

Accurate migration barriers for tungsten surface diffusion processes.

Validated KMC model reproduces nanocluster shapes consistent with MD.

Parameterization includes first-, second-, and third-nearest neighbor processes.

Abstract

We have calculated the migration barriers for surface diffusion on Tungsten. Our results form a self-sufficient parameterization for Kinetic Monte Carlo simulations of arbitrarily rough atomic tungsten surfaces, as well as nanostructures such as nanotips and nanoclusters. The parameterization includes first- and second-nearest neighbour atom jump processes, as well as a third-nearest neighbour exchange process. The migration energy barriers of all processes are calculated with the Nudged Elastic Band method. The same attempt frequency for all processes is found sufficient and the value is fitted to Molecular Dynamics simulations. The model is validated by correctly simulating with Kinetic Monte Carlo the energetically favourable W nanocluster shapes, in good agreement with Molecular Dynamics simulations.