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arXiv 2501.09288cond-mat.softcond-mat.dis-nncond-mat.mtrl-scicond-mat.stat-mech
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低温下,玻璃形成液体以简单方式发生弛豫

At low temperatures, glass-forming liquids relax in a simple way

Francesco Rusciano, Raffaele Pastore, Francesco Greco, Walter Kob

AI总结:

该研究通过大规模模拟将玻璃形成液体的弛豫动力学研究拓展至$T_c$以下温度,发现了新的弛豫机制与标度律,揭示了笼逸过程与大位移粒子的关联,深化了对近玻璃化转变温度下体系动力学的认知。

摘要:

玻璃形成液体的结晶倾向较弱,因此即便在熔点以下,其动力学行为也可被研究。大多数这类液体的弛豫动力学在略高于玻璃化转变温度$T_g$的温度$T_c$处表现出交叉现象,这标志着两种不同动力学区域的衔接。对于略高于$T_c$的温度区间,实验与计算机模拟已在粒子层面广泛探究了该动力学过程,识别出若干常与理论预测相符的普适标度律。\n我们通过大规模计算机模拟将这些研究拓展至$T_c$以下的温度,发现此处的弛豫机制与更高温度下的机制存在定性差异。我们识别出新的标度律,可对极低温度$T$下的弛豫动力学给出简洁描述。具体而言,我们揭示出笼逸过程与罕见但幅度较大的粒子位移相关,这些位移会在时间关联函数中产生独特的次扩散幂律行为。这一发现有助于推进我们对接近实验玻璃化转变温度下玻璃形成体系弛豫动力学的理解。

英文摘要:

Glass-forming liquids have only a modest tendency to crystallize and hence their dynamics can be studied even below the melting temperature. The relaxation dynamics of most of these liquids shows at a temperature $T_c$, somewhat above the glass-transition temperature $T_g$, a crossover, which indicates the conjunction of two different dynamical regimes. For temperatures slightly above $T_c$, experiments and computer simulations have extensively probed this dynamics on the particle level and identified several universal scaling laws that are often compatible with theoretical predictions. Using large scale computer simulations we extend these studies to temperatures below $T_c$ and find that the relaxation mechanism is qualitatively different from the one found at higher temperatures. We identify new scaling laws that allow to give a simple description of the relaxation dynamics at very low $T$s. Specifically we reveal that the cage-escape process is related to rare but large particle displacements that give rise to a distinctive sub-diffusive power-law in the time correlation functions. This insight helps to advance our understanding on the relaxation dynamics of glass-forming systems at temperatures that are close to the experimental glass transition.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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