ISSN:
1662-0356
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Natural Sciences in General
,
Technology
Notes:
TiO2 has been intensively studied as a wide band-gap transition metal oxide partially dueto the multi-valence nature of its cation. Here, density-functional theory calculations within thesupercell approximation are carried out to determine the preferred charge state of point defects inrutile TiO2. The first component of this work is to investigate the dependence of the defectformation energies on supercell size and the electrostatic Makov-Payne correction. The results showthat the Makov-Payne correction improves the convergence of defect formation energies as afunction of supercell size for positively charged titanium interstitials and negatively chargedtitanium vacancies. However, in the case of positively charged oxygen vacancies, applying theMakov-Payne correction gives the wrong sign for the defect formation energy correction. This isattributed to the shallow nature of the transition levels for this defect in TiO2. Finally, we combinethe calculated defect formation energies with thermodynamic data to evaluate the influence oftemperature on the relative stabilities of point defects. The results indicate that when the Makov-Payne correction is applied, a stable charge transition occurs for titanium interstitials. In addition, asthe temperature increases, the dominant point defect in TiO2 changes from oxygen vacancies totitanium interstitials
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.45.1.pdf
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