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Título:
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First principles calculations of the atomic and electronic structure of F centers in bulk and on the (001) surface of SrTiO3
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Autor/a:
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Carrasco Rodríguez, Javier; Illas i Riera, Francesc; López, Núria (López Alonso); Kotomin, E. A.; Zhukovskii, Yu. F.; Evarestov, R. A. (Robert Aleksandrovich); Mastrikov, Yu. A.; Piskunov, S.; Maier, J.
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Otros autores:
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Universitat de Barcelona |
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Abstract:
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The atomic and electronic structure, formation energy, and the energy barriers for migration have been
calculated for the neutral O vacancy point defect F center in cubic SrTiO3 employing various implementations
of density functional theory DFT. Both bulk and TiO2-terminated 001 surface F centers have been
considered. Supercells of different shapes containing up to 320 atoms have been employed. The limit of an
isolated single oxygen vacancy in the bulk corresponds to a 270-atom supercell, in contrast to commonly used
supercells containing 40–80 atoms. Calculations carried out with the hybrid B3PW functional show that the
F center level approaches the conduction band bottom to within 0.5 eV, as the supercell size increases up to
320 atoms. The analysis of the electronic density maps indicates, however, that this remains a small-radius
center with the two electrons left by the missing O ion being redistributed mainly between the vacancy and the
3d z2 atomic orbitals of the two nearest Ti ions. As for the dynamical properties, the calculated migration
energy barrier in the low oxygen depletion regime is predicted to be 0.4 eV. In contrast, the surface F center
exhibits a more delocalized character, which leads to significantly reduced ionization and migration energies.
Results obtained are compared with available experimental data. |
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Materia(s):
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-Estructura electrònica
-Estructura atòmica
-Electronic structure
-Atomic structure |
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Derechos:
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(c) The American Physical Society, 2006
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Tipo de documento:
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Artículo
Artículo - Versión publicada |
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Editor:
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The American Physical Society
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Compartir:
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