Berthier Ludovic, Ozawa Misaki, Scalliet Camille
Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, France.
J Chem Phys. 2019 Apr 28;150(16):160902. doi: 10.1063/1.5091961.
The configurational entropy is one of the most important thermodynamic quantities characterizing supercooled liquids approaching the glass transition. Despite decades of experimental, theoretical, and computational investigation, a widely accepted definition of the configurational entropy is missing, its quantitative characterization remains fraught with difficulties, misconceptions, and paradoxes, and its physical relevance is vividly debated. Motivated by recent computational progress, we offer a pedagogical perspective on the configurational entropy in glass-forming liquids. We first explain why the configurational entropy has become a key quantity to describe glassy materials, from early empirical observations to modern theoretical treatments. We explain why practical measurements necessarily require approximations that make its physical interpretation delicate. We then demonstrate that computer simulations have become an invaluable tool to obtain precise, nonambiguous, and experimentally relevant measurements of the configurational entropy. We describe a panel of available computational tools, offering for each method a critical discussion. This perspective should be useful to both experimentalists and theoreticians interested in glassy materials and complex systems.
构型熵是表征接近玻璃化转变的过冷液体的最重要的热力学量之一。尽管经过了数十年的实验、理论和计算研究，但构型熵仍缺乏一个被广泛接受的定义，其定量表征仍然充满困难、误解和悖论，其物理相关性也存在激烈的争论。受近期计算进展的推动，我们提供了一个关于玻璃形成液体中构型熵的教学视角。我们首先解释了为什么从早期的经验观察到现代理论处理，构型熵已成为描述玻璃态材料的关键量。我们解释了为什么实际测量必然需要近似，这使得其物理解释变得微妙。然后我们证明，计算机模拟已成为获得构型熵精确、明确且与实验相关测量的宝贵工具。我们描述了一系列可用的计算工具，并对每种方法进行了批判性讨论。这一视角对于对玻璃态材料和复杂系统感兴趣的实验人员和理论人员都应是有用的。
