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Title
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Origin of magnetism and quasiparticles properties in Cr-doped
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Author
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Abstract
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| Combining the local spin density approximation (LSDA)+U and an analysis of superexchange interactions beyond density functional theory, we describe the magnetic ground state of Cr-doped TiO2, an intensively studied and debated dilute magnetic oxide. In parallel, we correct our LSDA+U (+ superexchange) ground state through GW corrections (GW@LSDA+U) that reproduce the position of the impurity states and the band gaps in satisfying agreement with experiments. Because of the different topological coordinations of Cr-Cr bonds in the ground states of rutile and anatase, superexchange interactions induce either ferromagnetic or antiferromagnetic couplings of Cr ions. In Cr-doped anatase, this interaction leads to a new mechanism which stabilizes a (nonrobust) ferromagnetic ground state, in keeping with experimental evidence, without the need to invoke F-center exchange. The interplay between structural defects and vacancies in contributing to the superexchange is also unveiled. |
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Language
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English
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Source (journal)
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Physical review letters. - New York, N.Y., 1958, currens
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Publication
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New York, N.Y.
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American Physical Society
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2013
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ISSN
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0031-9007
[print]
1079-7114
[online]
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DOI
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10.1103/PHYSREVLETT.110.136402
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Volume/pages
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110
:13
(2013)
, p. 1-5
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Article Reference
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136402
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ISI
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000316683500014
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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