Analysis of Intrinsic Defects in CeO2 Using a Koopmans-Like GGA+U Approach
| Autor: | Patrick R. L. Keating, Natasha M. Galea, David O. Scanlon, Graeme W. Watson, Benjamin J. Morgan |
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| Rok vydání: | 2012 |
| Předmět: |
Chemistry
Ab initio chemistry.chemical_element Electron Oxygen Molecular physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials Ion Molecular dynamics General Energy Temperature and pressure Electrical resistivity and conductivity Computational chemistry Density functional theory Physical and Theoretical Chemistry |
| Zdroj: | The Journal of Physical Chemistry C. 116:2443-2452 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp2080034 |
| Popis: | We have investigated the formation of intrinsic defects in CeO2 using density functional theory with the generalized gradient approximation (GGA) corrected for on-site Coulombic interactions (GGA+U). We employed an ab initio fitting procedure to determine a U{O2p} value that satisfies a Koopmans-like condition and obtained a value of U{O2p} = 5.5 eV. We subsequently demonstrated that by applying GGA+U to the O2p states, in addition to the Ce4f states, we were able to model localized holes in addition to localized electrons, thus improving the description of p-type defects in CeO2. Our results show that under oxygen-poor conditions the defects with the lowest formation energy are oxygen vacancies, while oxygen interstitials, which form peroxide ions, will be more favorable under oxygen-rich conditions. We carried out temperature and pressure dependence analyses to determine the relative abundance of intrinsic defects under real-world conditions and determined that oxygen vacancies will always be the domina... |
| Databáze: | OpenAIRE |
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