Fast equilibration mechanisms in disordered materials mediated by slow liquid dynamics

The rate at which a nonequilibrium system decreases its free energy is commonly ascribed to molecular relaxation processes, arising from spontaneous rearrangements at the microscopic scale. While equilibration of liquids usually requires density fluctuations at time scales quickly diverging upon coo...

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Bibliographic Details
Published in:Science advances 2022-04, Vol.8 (15), p.eabm7154-eabm7154
Main Authors: Song, Zijian, Rodríguez-Tinoco, Cristian, Mathew, Allen, Napolitano, Simone
Format: Article
Language:English
Subjects:
Condensed Matter Physics
Materials Science
Physical and Materials Sciences
SciAdv r-articles
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Summary:The rate at which a nonequilibrium system decreases its free energy is commonly ascribed to molecular relaxation processes, arising from spontaneous rearrangements at the microscopic scale. While equilibration of liquids usually requires density fluctuations at time scales quickly diverging upon cooling, growing experimental evidence indicates the presence of a different, alternative pathway of weaker temperature dependence. Such equilibration processes exhibit a temperature-invariant activation energy, on the order of 100 kJ mol . Here, we identify the underlying molecular process responsible for this class of Arrhenius equilibration mechanisms with a slow mode (SAP), universally observed in the liquid dynamics of thin films. The SAP, which we show is intimately connected to high-temperature flow, can efficiently drive melts and glasses toward more stable, less energetic states. Our results show that measurements of liquid dynamics can be used to predict the equilibration rate in the glassy state.
ISSN:2375-2548
2375-2548
DOI:10.1126/sciadv.abm7154