Prediction of high-temperature point defect formation in TiO2 from combined ab initio and thermodynamic calculations

J. He, R. K. Behera, M. W. Finnis, X. Li, E. C. Dickey, S. R. Phillpot, S. B. Sinnott

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

A computational approach that integrates ab initio electronic structure and thermodynamic calculations is used to determine point defect stability in rutile TiO2 over a range of temperatures, oxygen partial pressures and stoichiometries. Both donors (titanium interstitials and oxygen vacancies) and acceptors (titanium vacancies) are predicted to have shallow defect transition levels in the electronic-structure calculations. The resulting defect formation energies for all possible charge states are then used in thermodynamic calculations to predict the influence of temperature and oxygen partial pressure on the relative stabilities of the point defects. Their ordering is found to be the same as temperature increases and oxygen partial pressure decreases: titanium vacancy → oxygen vacancy → titanium interstitial. The charges on these defects, however, are quite sensitive to the Fermi level. Finally, the combined formation energies of point defect complexes, including Schottky, Frenkel and anti-Frenkel defects, are predicted to limit the further formation of point defects.

Original languageEnglish (US)
Pages (from-to)4325-4337
Number of pages13
JournalActa Materialia
Volume55
Issue number13
DOIs
StatePublished - Aug 1 2007

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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