Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3

The formation energy, geometry, and electronic structure of isolated oxygen and aluminum vacancies in bulk and on the (0001) surface of corundum ( α − Al 2 O 3 ) have been investigated by means of periodic calculations in the framework of density functional theory within the generalized gradient app...

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Autores: Carrasco Rodríguez, Javier, Gomes, José R. B., Illas i Riera, Francesc
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2004
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/10815
Acceso en línea:https://hdl.handle.net/2445/10815
Access Level:acceso abierto
Palabra clave:Estructura electrònica
Òxids metàl·lics
Electronic structure
Metallic oxides
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spelling Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3Carrasco Rodríguez, JavierGomes, José R. B.Illas i Riera, FrancescEstructura electrònicaÒxids metàl·licsElectronic structureMetallic oxidesThe formation energy, geometry, and electronic structure of isolated oxygen and aluminum vacancies in bulk and on the (0001) surface of corundum ( α − Al 2 O 3 ) have been investigated by means of periodic calculations in the framework of density functional theory within the generalized gradient approximation and large supercells. The energy cost to form an oxygen vacancy in the bulk is estimated to be of the order of 10 eV, whereas that corresponding to the formation of Al vacancies is found to be at least a 30% larger. The relaxation of the material is rather small for both defects. The removal of an oxygen atom in bulk α − Al 2 O 3 is accompanied by the appearance of an impurity level in the gap, which is a strong indication of electron localization. This has been further confirmed by integration of the density of states in the energy interval corresponding to the impurity level and by several other theoretical analyses. For the α − Al 2 O 3 ( 0001 ) surface, the formation of oxygen and aluminum vacancies exhibits many similarities with the bulk; the energy cost to form Al vacancies is much larger than for O vacancies and, in both cases, it is accompanied by rather small atomic displacements. However, there are also significant differences between bulk and surface oxygen and aluminum vacancies. Thus the formation energy of one of these point defects in the surface is rather smaller as expected and, more importantly, the degree of electronic delocalization is also larger.The American Physical Society2004info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/10815Articles publicats en revistes (Ciència dels Materials i Química Física)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.69.064116Physical Review B, 2004, vol. 69, núm. 6, p. 064116-1-064116-13http://dx.doi.org/10.1103/PhysRevB.69.064116(c) The American Physical Society, 2004info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/108152026-05-27T06:46:51Z
dc.title.none.fl_str_mv Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
title Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
spellingShingle Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
Carrasco Rodríguez, Javier
Estructura electrònica
Òxids metàl·lics
Electronic structure
Metallic oxides
title_short Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
title_full Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
title_fullStr Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
title_full_unstemmed Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
title_sort Theoretical study of bulk and surface oxygen and aluminium vacancies in (alpha)-Al2O3
dc.creator.none.fl_str_mv Carrasco Rodríguez, Javier
Gomes, José R. B.
Illas i Riera, Francesc
author Carrasco Rodríguez, Javier
author_facet Carrasco Rodríguez, Javier
Gomes, José R. B.
Illas i Riera, Francesc
author_role author
author2 Gomes, José R. B.
Illas i Riera, Francesc
author2_role author
author
dc.subject.none.fl_str_mv Estructura electrònica
Òxids metàl·lics
Electronic structure
Metallic oxides
topic Estructura electrònica
Òxids metàl·lics
Electronic structure
Metallic oxides
description The formation energy, geometry, and electronic structure of isolated oxygen and aluminum vacancies in bulk and on the (0001) surface of corundum ( α − Al 2 O 3 ) have been investigated by means of periodic calculations in the framework of density functional theory within the generalized gradient approximation and large supercells. The energy cost to form an oxygen vacancy in the bulk is estimated to be of the order of 10 eV, whereas that corresponding to the formation of Al vacancies is found to be at least a 30% larger. The relaxation of the material is rather small for both defects. The removal of an oxygen atom in bulk α − Al 2 O 3 is accompanied by the appearance of an impurity level in the gap, which is a strong indication of electron localization. This has been further confirmed by integration of the density of states in the energy interval corresponding to the impurity level and by several other theoretical analyses. For the α − Al 2 O 3 ( 0001 ) surface, the formation of oxygen and aluminum vacancies exhibits many similarities with the bulk; the energy cost to form Al vacancies is much larger than for O vacancies and, in both cases, it is accompanied by rather small atomic displacements. However, there are also significant differences between bulk and surface oxygen and aluminum vacancies. Thus the formation energy of one of these point defects in the surface is rather smaller as expected and, more importantly, the degree of electronic delocalization is also larger.
publishDate 2004
dc.date.none.fl_str_mv 2004
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/10815
url https://hdl.handle.net/2445/10815
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.69.064116
Physical Review B, 2004, vol. 69, núm. 6, p. 064116-1-064116-13
http://dx.doi.org/10.1103/PhysRevB.69.064116
dc.rights.none.fl_str_mv (c) The American Physical Society, 2004
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) The American Physical Society, 2004
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv The American Physical Society
publisher.none.fl_str_mv The American Physical Society
dc.source.none.fl_str_mv Articles publicats en revistes (Ciència dels Materials i Química Física)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301629

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