Thermal expansion and the glass transition

Peter Lunkenheimer*, Alois Loidl, Birte Riechers, Alessio Zaccone, Konrad Samwer

*Corresponding author

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstract

Melting is well understood in terms of the Lindemann criterion, which essentially states that crystalline materials melt when the thermal vibrations of their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies. Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa.

OriginalsprogEngelsk
TidsskriftNature Physics
Vol/bind19
Udgave nummer5
Sider (fra-til)694–699
Antal sider6
ISSN1745-2473
DOI
StatusUdgivet - maj 2023

Bibliografisk note

Any methods, additional references, Nature Portfolio reporting sum-
maries, source data, extended data, supplementary information,
acknowledgements, peer review information; details of author contri-
butions and competing interests; and statements of data and code avail-
ability are available at https://doi.org/10.1038/s41567-022-01920-5.

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