Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500107, India.
Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Japan.
Phys Rev Lett. 2018 Aug 24;121(8):085703. doi: 10.1103/PhysRevLett.121.085703.
The origin of the rapid dynamical slowdown in glass forming liquids in the growth of static length scales, possibly associated with identifiable structural ordering, is a much debated issue. Growth of medium range crystalline order (MRCO) has been observed in various model systems to be associated with glassy behavior. Such observations raise the question of whether molecular mechanisms for the glass transition in liquids with and without MRCO are the same. In this study we perform extensive molecular dynamics simulations of a number of glass forming liquids and show that the static and dynamic properties of glasses with MRCO are different from those of other glass forming liquids with no predominant local order. We also resolve an important issue regarding the so-called point-to-set method for determining static length scales, and demonstrate it to be a robust method for determining static correlation lengths in glass formers.
在静态长度尺度的增长中,玻璃形成液体的快速动力学减速的起源,可能与可识别的结构有序性有关,这是一个备受争议的问题。在各种模型系统中已经观察到中等范围有序结构(MRCO)的生长与玻璃态行为有关。这些观察提出了一个问题,即在具有和不具有 MRCO 的液体中,玻璃化转变的分子机制是否相同。在这项研究中,我们对一些玻璃形成液体进行了广泛的分子动力学模拟,结果表明,具有 MRCO 的玻璃的静态和动态性质与其他没有主要局部有序的玻璃形成液体不同。我们还解决了关于所谓的点到集合方法确定静态长度尺度的一个重要问题,并证明它是一种确定玻璃形成体静态相关长度的稳健方法。