论文标题
Kob-Andersen二元混合物玻璃液体的动力学交叉
Crossover in dynamics in the Kob-Andersen binary mixture glass-forming liquid
论文作者
论文摘要
玻璃形成的液体被广泛地归类为脆弱或强的，这取决于其放松时间的偏离。在水和二氧化硅等液体中观察到或推断出脆弱的跨界，以及最近在金属玻璃和相变合金中，导致人们期望这种交叉在玻璃板中更广泛地实现。我们在计算上研究了良好的Kob-Andersen模型，访问远低于模式耦合温度的温度$ t_ {mct} $。我们发现，放松时间在$ t_ {mct} $左右的动力学中表现出一个交叉，并讨论它是否具有脆弱的特征到强跨界的特征。动力学异质性的几个方面表现出反映动态交叉的行为，而热力学量则没有。特别是，当包括对振动熵的核心校正时，描述了放松时间和配置熵之间关系的Adam-Gibbs关系继续保持在动态跨界的下方。
Glass-forming liquids are broadly classified as being fragile or strong, depending on the deviation from Arrhenius behavior of their relaxation times. A fragile to strong crossover is observed or inferred in liquids like water and silica, and more recently also in metallic glasses and phase change alloys, leading to the expectation that such a crossover is more widely realised among glass formers. We investigate computationally the well-studied Kob-Andersen model, accessing temperatures well below the mode coupling temperature $T_{MCT}$. We find that relaxation times exhibit a crossover in dynamics around $T_{MCT}$, and discuss whether it bears characteristics of the fragile to strong crossover. Several aspects of dynamical heterogeneity exhibit behavior mirroring the dynamical crossover, whereas thermodynamic quantities do not. In particular, the Adam-Gibbs relation describing the relation between relaxation times and configurational entropy continues to hold below the dynamical crossover, when anharmonic corrections to the vibrational entropy are included.
