论文标题
固有状态熔化和二维超冷液体中玻璃动力学的发作
Inherent-State Melting and the Onset of Glassy Dynamics in Two-Dimensional Supercooled Liquids
论文作者
论文摘要
在开始温度下方$ t_ \ text {o} $下方，大多数玻璃形成液体的平衡松弛时间表现出以超级arrhenius温度依赖性为特征的玻璃动力学。在这个超冷的制度中，放松动力学还通过与固有状态之间的跳跃事件相对应的局部弹性激发进行，即潜在的能量最小化液体的构型。尽管它在将超冷的制度与高温制度区分开来，但尚不清楚$ t_ \ text {o} $的微观起源。在这里，我们在两个维度上构建了一个关于开始温度的理论，发现固有状态熔化的转变是通过偶极弹性激发的结合无结合过渡描述的，从高温方向上描述了超冷的态度。相应的熔化过渡温度与在玻璃板的各种二维原子模型中发现的开始温度非常吻合。我们讨论了我们关于二维超冷液体位移和密度相关性的理论的预测，这些液体与最近的实验和分子模拟中对Mermin-Wagner波动的观察一致。
Below the onset temperature $T_\text{o}$, the equilibrium relaxation time of most glass-forming liquids exhibits glassy dynamics characterized by super-Arrhenius temperature dependence. In this supercooled regime, the relaxation dynamics also proceeds through localized elastic excitations corresponding to hopping events between inherent states, i.e., potential-energy minimizing configurations of the liquid. Despite its importance in distinguishing the supercooled regime from the high-temperature regime, the microscopic origin of $T_\text{o}$ is not yet known. Here, we construct a theory for the onset temperature in two dimensions and find that inherent-state melting transition, described by the binding-unbinding transition of dipolar elastic excitations, delineates the supercooled regime from the high-temperature regime. The corresponding melting transition temperature is in good agreement with the onset temperature found in various two-dimensional atomistic models of glass formers. We discuss the predictions of our theory on the displacement and density correlations of two-dimensional supercooled liquids, which are consistent with observations of the Mermin-Wagner fluctuations in recent experiments and molecular simulations.
