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| Format: | Preprint |
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2023
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| Online-Zugang: | https://arxiv.org/abs/2307.10143 |
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| _version_ | 1866916037372411904 |
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| author | Parmar, Anshul D. S. Kellers, Simon G. Heuer, Andreas |
| author_facet | Parmar, Anshul D. S. Kellers, Simon G. Heuer, Andreas |
| contents | A microscopic understanding of low-temperature thermodynamics and its relation to dynamical features such as a fragile-to-strong crossover (FSC) remains a central challenge in glass physics. Using swap Monte Carlo combined with a full potential-energy-landscape (PEL) analysis of a non-network-forming model, we obtain equilibrium data deep into the glassy regime and identify a finite system size that simultaneously reproduces bulk behaviour for $T \gtrsim T_g/2$ and allows complete sampling of the PEL down to its lowest-energy amorphous states. This enables the direct computation of the configurational entropy over the full temperature range of the finite system without relying on liquid-state thermodynamic integration. We find a pronounced depletion of low-energy states relative to the Gaussian regime of the PEL, which governs the low-temperature curvature of the configurational entropy. Numerically, the apparent activation energy of the diffusivity closely follows the temperature dependence of the mean inherent structure energy and exhibits a gradual crossover towards Arrhenius-like behaviour. This correlation is consistent with a trap-model description of the PEL, in which the FSC emerges naturally as a consequence of the depletion of low-energy states and thus of the lower bound of the PEL. We further argue, as illustrated analytically for a simple binomial model of the PEL, that the observability of a FSC depends on whether the depletion regime is reached within the accessible temperature window. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_10143 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Starting from the amorphous ground state: linking landscape thermodynamics to slow dynamics and crossover Parmar, Anshul D. S. Kellers, Simon G. Heuer, Andreas Soft Condensed Matter Disordered Systems and Neural Networks Materials Science A microscopic understanding of low-temperature thermodynamics and its relation to dynamical features such as a fragile-to-strong crossover (FSC) remains a central challenge in glass physics. Using swap Monte Carlo combined with a full potential-energy-landscape (PEL) analysis of a non-network-forming model, we obtain equilibrium data deep into the glassy regime and identify a finite system size that simultaneously reproduces bulk behaviour for $T \gtrsim T_g/2$ and allows complete sampling of the PEL down to its lowest-energy amorphous states. This enables the direct computation of the configurational entropy over the full temperature range of the finite system without relying on liquid-state thermodynamic integration. We find a pronounced depletion of low-energy states relative to the Gaussian regime of the PEL, which governs the low-temperature curvature of the configurational entropy. Numerically, the apparent activation energy of the diffusivity closely follows the temperature dependence of the mean inherent structure energy and exhibits a gradual crossover towards Arrhenius-like behaviour. This correlation is consistent with a trap-model description of the PEL, in which the FSC emerges naturally as a consequence of the depletion of low-energy states and thus of the lower bound of the PEL. We further argue, as illustrated analytically for a simple binomial model of the PEL, that the observability of a FSC depends on whether the depletion regime is reached within the accessible temperature window. |
| title | Starting from the amorphous ground state: linking landscape thermodynamics to slow dynamics and crossover |
| topic | Soft Condensed Matter Disordered Systems and Neural Networks Materials Science |
| url | https://arxiv.org/abs/2307.10143 |