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Entropic elasticity and negative thermal expansion in a simple cubic crystal

While most solids expand when heated, some materials show the opposite behavior: negative thermal expansion (NTE). In polymers and biomolecules, NTE originates from the entropic elasticity of an ideal, freely jointed chain. The origin of NTE in solids has been widely believed to be different. Our ne...

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Autores principales: Wendt, David, Bozin, Emil, Neuefeind, Joerg, Page, Katharine, Ku, Wei, Wang, Limin, Fultz, Brent, Tkachenko, Alexei V., Zaliznyak, Igor A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824856/
https://www.ncbi.nlm.nih.gov/pubmed/31701009
http://dx.doi.org/10.1126/sciadv.aay2748
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author Wendt, David
Bozin, Emil
Neuefeind, Joerg
Page, Katharine
Ku, Wei
Wang, Limin
Fultz, Brent
Tkachenko, Alexei V.
Zaliznyak, Igor A.
author_facet Wendt, David
Bozin, Emil
Neuefeind, Joerg
Page, Katharine
Ku, Wei
Wang, Limin
Fultz, Brent
Tkachenko, Alexei V.
Zaliznyak, Igor A.
author_sort Wendt, David
collection PubMed
description While most solids expand when heated, some materials show the opposite behavior: negative thermal expansion (NTE). In polymers and biomolecules, NTE originates from the entropic elasticity of an ideal, freely jointed chain. The origin of NTE in solids has been widely believed to be different. Our neutron scattering study of a simple cubic NTE material, ScF(3), overturns this consensus. We observe that the correlation in the positions of the neighboring fluorine atoms rapidly fades on warming, indicating an uncorrelated thermal motion constrained by the rigid Sc-F bonds. This leads us to a quantitative theory of NTE in terms of entropic elasticity of a floppy network crystal, which is in remarkable agreement with experimental results. We thus reveal the formidable universality of the NTE phenomenon in soft and hard matter.
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spelling pubmed-68248562019-11-07 Entropic elasticity and negative thermal expansion in a simple cubic crystal Wendt, David Bozin, Emil Neuefeind, Joerg Page, Katharine Ku, Wei Wang, Limin Fultz, Brent Tkachenko, Alexei V. Zaliznyak, Igor A. Sci Adv Research Articles While most solids expand when heated, some materials show the opposite behavior: negative thermal expansion (NTE). In polymers and biomolecules, NTE originates from the entropic elasticity of an ideal, freely jointed chain. The origin of NTE in solids has been widely believed to be different. Our neutron scattering study of a simple cubic NTE material, ScF(3), overturns this consensus. We observe that the correlation in the positions of the neighboring fluorine atoms rapidly fades on warming, indicating an uncorrelated thermal motion constrained by the rigid Sc-F bonds. This leads us to a quantitative theory of NTE in terms of entropic elasticity of a floppy network crystal, which is in remarkable agreement with experimental results. We thus reveal the formidable universality of the NTE phenomenon in soft and hard matter. American Association for the Advancement of Science 2019-11-01 /pmc/articles/PMC6824856/ /pubmed/31701009 http://dx.doi.org/10.1126/sciadv.aay2748 Text en Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). http://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (http://creativecommons.org/licenses/by-nc/4.0/) , which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
spellingShingle Research Articles
Wendt, David
Bozin, Emil
Neuefeind, Joerg
Page, Katharine
Ku, Wei
Wang, Limin
Fultz, Brent
Tkachenko, Alexei V.
Zaliznyak, Igor A.
Entropic elasticity and negative thermal expansion in a simple cubic crystal
title Entropic elasticity and negative thermal expansion in a simple cubic crystal
title_full Entropic elasticity and negative thermal expansion in a simple cubic crystal
title_fullStr Entropic elasticity and negative thermal expansion in a simple cubic crystal
title_full_unstemmed Entropic elasticity and negative thermal expansion in a simple cubic crystal
title_short Entropic elasticity and negative thermal expansion in a simple cubic crystal
title_sort entropic elasticity and negative thermal expansion in a simple cubic crystal
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824856/
https://www.ncbi.nlm.nih.gov/pubmed/31701009
http://dx.doi.org/10.1126/sciadv.aay2748
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