Loosing thermodynamic stability in amorphous materials
The primary relaxation dynamics near the glass transformation temperature T g exhibits universal features in all glass formers, when showing two-level tunneling states (Low Temp. Phys. 35, 282 (2009)). Researchers have long searched for any signature of the underlying “true” ergodic–nonergodic trans...
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| Date: | 2011 |
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| Main Author: | |
| Format: | Article |
| Language: | English |
| Published: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2011
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| Series: | Физика низких температур |
| Subjects: | |
| Online Access: | http://dspace.nbuv.gov.ua/handle/123456789/118550 |
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| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Loosing thermodynamic stability in amorphous materials / V.B. Kokshenev // Физика низких температур. — 2011. — Т. 37, № 5. — С. 551–557. — Бібліогр.: 26 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| Summary: | The primary relaxation dynamics near the glass transformation temperature T g exhibits universal features in all glass formers, when showing two-level tunneling states (Low Temp. Phys. 35, 282 (2009)). Researchers have long searched for any signature of the underlying “true” ergodic–nonergodic transition emerging at a certain thermodynamic instability temperature Te . Here, the relaxation timescale for glass-forming materials is analyzed within a self-consistent thermodynamic cluster description combined with the cluster percolation concept. Exploring the ergodic hypothesis, its violation is found near a crossover from the Gaussian to non-Gaussian (Poisson) cluster-volume fluctuations, describing the finite-size fractal-cluster distributions. The transformation of the compact-structure “ergodic” clusters into hole-like glassy nanoclusters is attributed to the critical-size thermal fluctuations. The ergodic–nonergodic phase diagram showing Te is predicted in the model-independent form through the glass fragility parameter known for organic and inorganic liquids and amorphous solids. In all cases the ergodic-instability temperature is located below and close to the glass transformation temperature, whereas the distance between the two characteristic temperatures decreases with growing the material fragility. |
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