Malins Alex, Eggers Jens, Tanaka Hajime, Royall C Patrick
Faraday Discuss. 2013;167:405-23. doi: 10.1039/c3fd00078h.
We use a newly-developed method to identify local structural motifs in a popular model glassformer, the Kob-Andersen binary Lennard-Jones mixture. By measuring the lifetimes of a zoo of clusters, we find that 11-membered bicapped square antiprisms, denoted as 11A, have longer lifetimes on average than other structures considered. Other long-lived clusters are similar in structure to the 11A cluster. These clusters group into ramified networks that are correlated with slow particles and act to retard the motion of neighbouring particles. The structural lengthscale associated with these networks does not grow as fast as the dynamical lengthscale xi(4) as the system is cooled, in the range of temperatures our molecular dynamics simulations access. Thus we find a strong, but indirect, correlation between static structural ordering and slow dynamics.
我们使用一种新开发的方法来识别一种常见的模型玻璃形成体——科布-安德森二元 Lennard-Jones 混合物中的局部结构基序。通过测量一系列团簇的寿命，我们发现被标记为 11A 的 11 元双帽方反棱柱平均寿命比其他所考虑的结构更长。其他长寿命团簇在结构上与 11A 团簇相似。这些团簇聚集成分支网络，这些网络与慢粒子相关，并起到阻碍相邻粒子运动的作用。在我们分子动力学模拟所涉及的温度范围内，随着系统冷却，与这些网络相关的结构长度尺度的增长速度不如动力学长度尺度 ξ(4)快。因此，我们发现静态结构有序与慢动力学之间存在强烈但间接的相关性。
