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Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite

The benefit of computational methods applying density functional theory for the description and understanding of modulated crystal structures is investigated. A method is presented which allows one to establish, improve and test superspace models including displacive and occupational modulation func...

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Detalles Bibliográficos
Autores principales: Klar, Paul Benjamin, Etxebarria, Iñigo, Madariaga, Gotzon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396396/
https://www.ncbi.nlm.nih.gov/pubmed/30821259
http://dx.doi.org/10.1107/S2053273319000846
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author Klar, Paul Benjamin
Etxebarria, Iñigo
Madariaga, Gotzon
author_facet Klar, Paul Benjamin
Etxebarria, Iñigo
Madariaga, Gotzon
author_sort Klar, Paul Benjamin
collection PubMed
description The benefit of computational methods applying density functional theory for the description and understanding of modulated crystal structures is investigated. A method is presented which allows one to establish, improve and test superspace models including displacive and occupational modulation functions from first-principles calculations on commensurate structures. The total energies of different configurations allow one to distinguish stable and less stable structure models. The study is based on a series of geometrically optimized superstructures of mullite (Al(4+2x)Si(2−2x)O(10−x)) derived from the superspace group Pbam(α0½)0ss. Despite the disordered and structurally complex nature of mullite, the calculations on ordered superstructures are very useful for determining the ideal Al/Si ordering in mullite, extracting atomic modulation functions as well as understanding the SiO(2)–Al(2)O(3) phase diagram. The results are compared with experimentally established models which confirm the validity and utility of the presented method.
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spelling pubmed-63963962019-03-13 Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite Klar, Paul Benjamin Etxebarria, Iñigo Madariaga, Gotzon Acta Crystallogr A Found Adv Research Papers The benefit of computational methods applying density functional theory for the description and understanding of modulated crystal structures is investigated. A method is presented which allows one to establish, improve and test superspace models including displacive and occupational modulation functions from first-principles calculations on commensurate structures. The total energies of different configurations allow one to distinguish stable and less stable structure models. The study is based on a series of geometrically optimized superstructures of mullite (Al(4+2x)Si(2−2x)O(10−x)) derived from the superspace group Pbam(α0½)0ss. Despite the disordered and structurally complex nature of mullite, the calculations on ordered superstructures are very useful for determining the ideal Al/Si ordering in mullite, extracting atomic modulation functions as well as understanding the SiO(2)–Al(2)O(3) phase diagram. The results are compared with experimentally established models which confirm the validity and utility of the presented method. International Union of Crystallography 2019-02-12 /pmc/articles/PMC6396396/ /pubmed/30821259 http://dx.doi.org/10.1107/S2053273319000846 Text en © Paul Benjamin Klar et al. 2019 http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.http://creativecommons.org/licenses/by/4.0/
spellingShingle Research Papers
Klar, Paul Benjamin
Etxebarria, Iñigo
Madariaga, Gotzon
Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title_full Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title_fullStr Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title_full_unstemmed Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title_short Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
title_sort characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396396/
https://www.ncbi.nlm.nih.gov/pubmed/30821259
http://dx.doi.org/10.1107/S2053273319000846
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