Zheng Zhongyu, Ni Ran, Wang Yuren, Han Yilong
Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China.
Sci Adv. 2021 Jan 15;7(3). doi: 10.1126/sciadv.abd1958. Print 2021 Jan.
Critical-like behaviors have been found in translational degrees of freedom near the glass transition of spherical particle systems mainly with local polycrystalline structures, but it is not clear if criticality exists in more general glassy systems composed of nonspherical particles without crystalline structures. Here, through experiments and simulations, we show critical-like behaviors in both translational and rotational degrees of freedom in monolayers of monodisperse colloidal ellipsoids in the absence of crystalline orders. We find rich features of the Ising-like criticality in structure and slow dynamics at the ideal glass transition point ϕ, showing the thermodynamic nature of glass transition at ϕ A dynamic criticality is found at the mode-coupling critical point ϕ for the fast-moving clusters whose critical exponents increase linearly with fragility, reflecting a dynamic glass transition. These results cast light on the glass transition and explain the mystery that the dynamic correlation lengths diverge at two different temperatures.
在主要具有局部多晶结构的球形颗粒系统的玻璃化转变附近的平动自由度中发现了类似临界的行为,但尚不清楚在由无晶体结构的非球形颗粒组成的更一般的玻璃态系统中是否存在临界性。在此,通过实验和模拟,我们展示了在无晶体有序的单分散胶体椭球体单层中的平动和转动自由度中都存在类似临界的行为。我们在理想玻璃化转变点ϕ处的结构和慢动力学中发现了丰富的类伊辛临界特征,表明在ϕ处玻璃化转变的热力学性质。对于快速移动的团簇,在模式耦合临界点ϕ处发现了动态临界性,其临界指数随脆性线性增加,反映了动态玻璃化转变。这些结果揭示了玻璃化转变,并解释了动态关联长度在两个不同温度下发散的谜团。