A Phase Space Approach to Supercooled Liquids and a Universal Collapse of Their Viscosity
A Phase Space Approach to Supercooled Liquids and a Universal Collapse of Their Viscosity
复制标题
过冷液体的相空间方法及其粘度的普遍崩溃
作者：
N. B. Weingartner;C. Pueblo;F. Nogueira;K. Kelton;Z. Nussinov
尽管经过了数十年的深入探索，但对过冷液体现象学背后的机制的广泛基本理解仍然难以捉摸。当过冷到低于其特征熔化温度时，液体的粘度在很窄的温度范围内急剧上升，最终在实验室时间尺度上冻结。解释粘度的巨大增加是凝聚态物理学家的主要目标之一。为此，人们提出了许多理论框架来解释和重现过冷液体粘度的温度依赖性。这些框架中的每一个似乎仅适用于特定类别的玻璃形成剂，并且每个框架都具有许多可变参数。在这里，我们描述了一个经典框架，用于基于统计力学考虑来解释过冷液体的动力学行为，并且仅拥有单个可变参数。该参数随液体的不同而变化很小。此外，正如这一新经典理论及其早期量子对应物所预测的那样，我们发现，借助一个大小从 $sim 0.05-0.12$ 变化的小无量纲常数，粘度数据作为温度函数的普遍（16 个十年）崩溃。塌陷出现在所有已知类型的玻璃形成过冷液体（硅酸盐、金属合金、有机系统、硫属化物、糖和水）中。
A broad fundamental understanding of the mechanisms underlying the phenomenology of supercooled liquids has remained elusive, despite decades of intense exploration. When supercooled beneath its characteristic melting temperature, a liquid sees a sharp rise in its viscosity over a narrow temperature range, eventually becoming frozen on laboratory timescales. Explaining this immense increase in viscosity is one of the principle goals of condensed matter physicists. To that end, numerous theoretical frameworks have been proposed which explain and reproduce the temperature dependence of the viscosity of supercooled liquids. Each of these frameworks appears only applicable to specific classes of glassformers and each possess a number of variable parameters. Here we describe a classical framework for explaining the dynamical behavior of supercooled liquids based on statistical mechanical considerations, and possessing only a single variable parameter. This parameter varies weakly from liquid to liquid. Furthermore, as predicted by this new classical theory and its earlier quantum counterpart, we find with the aid of a small dimensionless constant that varies in size from $sim 0.05-0.12$, a universal (16 decade) collapse of the viscosity data as a function of temperature. The collapse appears in all known types of glass forming supercooled liquids (silicates, metallic alloys, organic systems, chalcogenide, sugars, and water).