Upper bound of fragility from spatial fluctuations of shear modulus and boson peak in glasses
Upper bound of fragility from spatial fluctuations of shear modulus and boson peak in glasses
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DOI：
10.1103/physreve.106.024611
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发表时间：
2022-08-31
影响因子：
2.4
通讯作者：
Novikov, V. N.
中科院分区：
文献类型：
--
作者：
Novikov, V. N.
结果表明，玻璃中剪切模量值在中程有序尺度上的归一化均方根起伏与脆性有关：脆性越高，起伏幅度越小。后者是在非均匀弹性理论中使用玻璃中玻色子峰值的数据计算的。在对应于协同结构松弛的较小尺度上，利用过冷液体中粘性和扩散解耦的数据估计了无限频率剪切模量值的归一化均方根涨落。这些波动的幅度要小得多，相反，它们随着脆弱性的增加而增加。外推预测均方根起伏和玻色子峰值消失的上限与脆性渐近到180的交集。
It is shown that the normalized rms fluctuation of the shear modulus on the medium-range order scale in glasses correlates with fragility: the higher fragility, the smaller the fluctuation amplitude. The latter is calculated within the heterogeneous elasticity theory using the data on the boson peak in glasses. On a smaller scale corresponding to cooperative structural relaxation, the normalized rms fluctuation of the infinite-frequency shear modulus was estimated using the data on the decoupling of viscosity and diffusion in supercooled liquids. These fluctuations are much smaller in amplitude, and, in contrast, they increase with increasing fragility. Extrapolation predicts intersection of both rms fluctuations and disappearing of the boson peak at the upper limit to fragility asymptotic to 180.