论文标题
重杂质对超冷液体动力学的影响
Effect of heavy impurities on the dynamics of supercooled liquids
论文作者
论文摘要
我们研究重杂质对超冷液体动力学的影响。当使超冷液体中的一小部分颗粒变重时，它们的动力学比原始粒子较慢，并且使整体系统较慢。如果人们查看重叠相关函数以量化系统中的动力学，则它对重粒子和光颗粒具有不同的行为。特别是，在整个系统的放松时间，较重的颗粒所达到的放松程度的平均水平低于光颗粒所获得的放松程度。然而，这种放松的差异大大降低，因为交叉温度（$ t_0 $）被交叉。在此交叉温度以下，系统中的颗粒的松弛时间与质量无关。该交叉温度取决于重颗粒及其质量的比例。接下来，我们分离质量异质性对超冷液体动力学的影响，发现其作用随温度而单调增加。我们还看到，随着温度降低的动态异质性的发展对于杂质的系统而言，与纯系统相比，杂质的戏剧性较小。最后，引入重杂质是减少超冷液体动力学脆弱性的一种方式。
We study the effect of heavy impurities on the dynamics of supercooled liquids. When a small fraction of particles in the supercooled liquid is made heavier, they exhibit slower dynamics than the original particles and also make the overall system slower. If one looks at the overlap correlation function to quantify dynamics in the system, it has different behavior for the heavy and the light particles. In particular, at the relaxation time of the overall system, the degree of relaxation achieved by the heavier particles is lesser on average than that achieved by the light particles. This difference in relaxation however, goes down drastically as a crossover temperature, $T_0$, is crossed. Below this crossover temperature, particles in the system have similar relaxation times irrespective of their masses. This crossover temperature depends on the fraction of the heavy particles and their masses. Next, we isolate the effect of mass heterogeneity on the dynamics of supercooled liquids and find that its effect increases monotonically with temperature. We also see that the development of dynamical heterogeneity with decreasing temperature is less dramatic for the system with impurities than for the pure system. Finally, the introduction of heavy impurities can be seen as a way of reducing the kinetic fragility of a supercooled liquid.
