A theoretical study of intrinsic point defects and defect clusters in magnesium aluminate spinel

Gilbert, C. A. and Smith, R. and Kenny, S. D. and Murphy, S. T. and Grimes, R. W. and Ball, J. A. (2009) A theoretical study of intrinsic point defects and defect clusters in magnesium aluminate spinel. Journal of Physics: Condensed Matter, 21 (27). ISSN 0953-8984

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Abstract

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.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Physics: Condensed Matter
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100/3104
Subjects:
ID Code:
125445
Deposited By:
Deposited On:
24 May 2018 12:24
Refereed?:
Yes
Published?:
Published
Last Modified:
11 Feb 2020 04:16