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|Title: ||Ab initio study of point defects in magnesium oxide|
|Authors: ||Gilbert, Christopher A.|
Kenny, Steven D.
|Issue Date: ||2007|
|Publisher: ||© The American Physical Society|
|Citation: ||GILBERT, C.A. ... et al., 2007. Ab initio study of point defects in magnesium oxide. Physical Review B (Condensed Matter and Materials Physics), 76 (18), 10pp.|
|Abstract: ||Energetics of a variety of point defects in MgO have been considered from an ab initio perspective using
density functional theory. The considered defects are isolated Schottky and Frenkel defects and interstitial
pairs, along with a number of Schottky defects and di-interstitials. Comparisons were made between the
density functional theory results and results obtained from empirical potential simulations and these generally
showed good agreement. Both methodologies predicted the first nearest neighbor Schottky defects to be the
most energetically favorable of the considered Schottky defects and that the first, second, and fifth nearest
neighbor di-interstitials were of similar energy and were favored over the other di-interstitial configurations.
Relaxed structures of the defects were analyzed, which showed that empirical potential simulations were
accurately predicting the displacements of atoms surrounding di-interstitials, but were overestimating O atom
displacement for Schottky defects. Transition barriers were computed for the defects using the nudged elastic
band method. Vacancies and Schottky defects were found to have relatively high energy barriers, the majority
of which were over 2 eV, in agreement with conclusions reached using empirical potentials. The lowest
barriers for di-interstitial transitions were found to be for migration into a first nearest neighbor configuration.
Charges were calculated using a Bader analysis and this found negligible charge transfer during the defect
transitions and only small changes in the charges on atoms surrounding defects, indicating why fixed charge
models work as well as they do.|
|Description: ||This article was published in the journal, Physical Review B (Condensed Matter and Materials Physics) [© The American Physical Society]. The definitive version is available at: http://dx.doi.org/10.1103/PhysRevB.76.184103|
|Publisher Link: ||http://dx.doi.org/10.1103/PhysRevB.76.184103|
|Appears in Collections:||Published Articles (Maths)|
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