Formation of double glass in binary mixtures of anisotropic particles : Dynamic heterogeneities in rotations and displacements
Formation of double glass in binary mixtures of anisotropic particles : Dynamic heterogeneities in rotations and displacements
复制标题
各向异性颗粒二元混合物中双玻璃的形成：旋转和位移的动态不均匀性
DOI：
10.1103/physreve.88.042317
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发表时间：
2013
影响因子：
2.4
通讯作者：
Kyohei Takae and Akira Onuki
中科院分区：
文献类型：
--
作者：
橋本洋輔;牧野兼三;大段秀顕;吉川純一;古澤明;Kyohei Takae and Akira Onuki
我们用取向相关的Lennard-Jones势研究了低温下二维椭圆和圆形粒子混合物中的玻璃行为。椭圆形具有温和的长宽比(在低温下倾向于取向)，而圆形粒子在浓度为这些杂质的尺寸比椭圆的尺寸小，并以同向排列吸引它们。因此，在玻璃态下，每个杂质周围的配位数大多为5或4。我们实现了双层玻璃，其中取向和位置都是无序的，但仍然保持介观有序。我们发现椭圆的翻转运动具有很强的不均一性，这种不均一性敏感地依赖于杂质的聚集。在我们的模型中，即使在低温下，一小部分椭圆仍然相对快速地发生翻转运动。相反，非翻转旋转(角度变化不太近)主要是由涉及多个粒子的协同构型变化引起的。然后，非翻转旋转的长期非均质性与位移的动态非均质性密切相关。
We study glass behavior in a mixture of elliptic and circular particles in two dimensions at low temperatures using an orientation-dependent Lennard-Jones potential. The ellipses have a mild aspect ratio (and tend to align at low temperatures, while the circular particles play the role of impurities disturbing the ellipse orientations at a concentration of. These impurities have a size smaller than that of the ellipses and attract them in the homeotropic alignment. As a result, the coordination number around each impurity is mostly 5 or 4 in glassy states. We realize double glass, where both the orientations and the positions are disordered but still hold mesoscopic order. We find a strong heterogeneity in the flip motions of the ellipses, which sensitively depends on the impurity clustering. In our model, a small fraction of the ellipses still undergo flip motions relatively rapidly even at low temperatures. In contrast, the nonflip rotations (with angle changes not close to) are mainly caused by the cooperative configuration changes involving many particles. Then, there arises a long-time heterogeneity in the nonflip rotations closely correlated with the dynamic heterogeneity in displacements.