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Adatoms and interstitials in the rutile TiO2 (110) surface: structure and dynamics

Mulheran, P.A. and Browne, C.S. and Moghaddam, Y. (2009) Adatoms and interstitials in the rutile TiO2 (110) surface: structure and dynamics. Molecular Simulation, 35 (7). pp. 532-537. ISSN 08927022

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Abstract

We present calculations for Ti adatoms and interstitials at the (110) surface of rutile TiO2, where these species are known to play a crucial role in surface chemistry. We review structural calculations performed using the DFT+U methodology, which have been benchmarked using controlled self-doping experiments on thin rutile films. The ab initio results have further been used to assess the ability of empirical charge equalisation (QEq) potentials to correctly predict the energetics of these structures. A simple modification to the potential, whereby the oxygen charge is fixed while allowing charge redistribution between Ti ions, has been shown to greatly improve its performance in terms of the energy landscape of the Ti adatoms and interstitials. In this paper, we extend the QEq calculations to consider the diffusion pathways and barriers in the surface using nudged elastic band calculations. We find that key barriers involved in the diffusion of Ti interstitials to adatom sites are much lower with the modified potential, implying that the diffusion is active on experimental time scales at temperatures where the regrowth of reduced rutile crystals exposed to oxygen has been observed.

Item type: Article
ID code: 15117
Keywords: titania, variable charge potential, density functional theory, Solid state physics. Nanoscience, Modelling and Simulation, Materials Science(all), Chemical Engineering(all), Chemistry(all), Information Systems, Condensed Matter Physics
Subjects: Science > Physics > Solid state physics. Nanoscience
Department: Faculty of Engineering > Chemical and Process Engineering
Related URLs:
    Depositing user: Dr Paul A Mulheran
    Date Deposited: 25 Jan 2010 14:04
    Last modified: 28 Mar 2014 05:12
    URI: http://strathprints.strath.ac.uk/id/eprint/15117

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