2134/19331
Christopher A. Gilbert
Christopher A.
Gilbert
Roger Smith
Roger
Smith
Steven Kenny
Steven
Kenny
S.T. Murphy
S.T.
Murphy
R.W. Grimes
R.W.
Grimes
J.A. Ball
J.A.
Ball
A theoretical study of intrinsic point defects and defect clusters in magnesium aluminate spinel
Loughborough University
2015
Magnesium aluminate spinel
Defects
DFT
Mathematical Sciences not elsewhere classified
Condensed Matter Physics
2015-11-06 15:14:15
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/A_theoretical_study_of_intrinsic_point_defects_and_defect_clusters_in_magnesium_aluminate_spinel/9388970
Point and small cluster defects in magnesium aluminate spinel have been studied from a first principles viewpoint. Typical point defects that occur during collision cascade simulations are cation anti-site defects, which have a small formation energy and are very stable, O and Mg split interstitials and vacancies. Isolated Al interstitials were found to be energetically unfavourable
but could occur as part of a split Mg-Al pair or as a three atom-three vacancy Al ‘ring’ defect, previously observed in collision cascades using empirical potentials. The structure and energetics
of the defects were investigated using density functional theory (DFT) and the results compared to simulations using empirical fixed-charge potentials. Each point defect was studied in a variety of supercell sizes in order to ensure convergence. It was found that empirical potential simulations significantly overestimate formation energies, but that the type and relative stability of the defects are well-predicted by the empirical potentials both for point defects and small defect clusters.