Improved Tight Binding Parametrization for the Simulation of Stacking Faults in Aluminium

TL;DR

This paper refines the tight binding model for aluminium by fitting it to high-accuracy DFT data, improving predictions of phase stability and stacking fault energies relevant for material deformation.

Contribution

It introduces a new tight binding parameterization for aluminium that better reproduces phase and defect energies by fitting to DFT calculations using a global optimization approach.

Findings

Improved prediction of hcp phase stability.

Enhanced accuracy in stacking fault energy calculations.

Better reproduction of bandstructure symmetries.

Abstract

We refit the NRL tight binding parameterization for Aluminium by Mehl \emph{et al} [Phys. Rev. B, 61, 4894 (2000)], to a database generated via full potential Linearized Augmented Plane Wave (LAPW) Density Functional Theory (DFT) calculations. This is performed using a global optimization algorithm paying particular attention to reproducing the correct order of the angular symmetries of the tight binding fcc and bcc bandstructure. The resulting parameterization is found to better predict the hcp phase and both the stable and unstable planar stacking fault defect energies.