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Ab initio modelling of defects in oxides

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thesis
posted on 02.11.2018, 12:25 by Christopher A. Gilbert
Two materials, magnesium oxide and magnesium aluminate spinel, have been studied using the ab initio methodology, density functional theory. In the case of MgO, energetics of a variety of point defects were considered. These defects were 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 neighbour Schottky defects to be the most energetically favourable of the considered Schottky defects and that the first, second, and fifth nearest neighbour di-interstitials were of similar energy and were favoured over the other di-interstitial configurations. Relaxed structures of the defects were analysed, which showed that empirical potential simulations were accurately predicting the displacements of atoms surrounding di-interstitials, but overestimated O atom displacement for Schottky defects. [Continues.]

Funding

Loughborough University.

History

School

  • Science

Department

  • Mathematical Sciences

Publisher

© Christopher Andrew Gilbert

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2009

Notes

A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of the degree of Doctor of Philosophy at Loughborough University.

Language

en

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