Energetics of point defects in aluminum via orbital-free density functional theory

TL;DR

This study systematically investigates the formation and migration energies of point defects in aluminum using orbital-free density functional theory, focusing on finite-size effects and functional accuracy to match experimental and Kohn-Sham results.

Contribution

It provides a detailed analysis of defect energetics in aluminum with orbital-free DFT, highlighting finite-size effects and the importance of kinetic energy functionals.

Findings

Finite-size errors decrease exponentially with supercell size.

Self-interstitial formation energies converge slower than vacancies.

Results align well with experimental and Kohn-Sham DFT data.

Abstract

The formation and migration energies for various point defects, including vacancies and self-interstitials in aluminum are reinvestigated systematically using the supercell approximation in the framework of orbital-free density functional theory. In particular, the finite-size effects and the accuracy of various kinetic energy density functionals are examined.The calculated results suggest that the errors due to the finite-size effect decrease exponentially upon enlarging the supercell. It is noteworthy that the formation energies of self-interstitials converge much slower than that of vacancy. With carefully chosen kinetic energy density functionals, the calculated results agree quite well with the available experimental data and those obtained by Kohn-Sham density functional theory which has exact kinetic term.