Quasi-harmonic vs. ``exact'' surface free energies of Al: a systematic study employing a new interatomic potential

TL;DR

This study introduces a new classical potential for aluminum that accurately models bulk and surface properties, and compares quasi-harmonic and Monte Carlo methods for surface free energy calculations.

Contribution

A novel interatomic potential for aluminum that matches experimental and ab initio data, and an analysis of the quasi-harmonic approximation's applicability to surface free energies.

Findings

Potential yields properties in excellent agreement with experiments and ab initio results.

Quasi-harmonic approximation's range of applicability is assessed against Monte Carlo results.

Surface free energy calculations for Al (100) surface at high temperatures.

Abstract

We discuss a computationally efficient classical many-body potential designed to model the Al-Al interaction in a wide range of bonding geometries. We show that the potential yields results in properties in excellent agreement with experiment and ab initio results for a number of bulk and surface properties, among others for surface and step formation energies, and self-diffusion barriers. As an application, free energy calculations are performed for the Al (100) surface by Monte Carlo thermodynamic integration and the quasi-harmonic approximation. Comparison of the latter approximation with the reference Monte Carlo results provides informations on its range of applicability to surface problems at high temperatures.