论文标题
通过动力学机械光谱揭示的非定位合作原子运动，该动作在非晶的tantala中进行了耗散
Non-local cooperative atomic motions that govern dissipation in amorphous tantala unveiled by dynamical mechanical spectroscopy
论文作者
论文摘要
通过分子动力学模拟研究了无定形tantala机械耗散的机制，即通过机械光谱在广泛的温度和频率下进行。我们发现，耗散与具有尖锐合作特征的不可逆原子重排有关，涉及在多面体的空间扩展簇中排列的数十个原子。值得注意的是，在低温下，我们观察到过多的塑料重排氧原子，这与宏观机械损耗中的实验峰有关。详细的结构分析揭示了不可逆转地重新排列的多面体的优先连接，对应于边缘和面部共享。这些结果可能会导致微观知情的设计规则，以减少与结构，光学和感应应用相关材料中的机械损失。
The mechanisms governing mechanical dissipation in amorphous tantala are studied at microscopic scale via Molecular Dynamics simulations, namely by mechanical spectroscopy in a wide range of temperature and frequency. We find that dissipation is associated with irreversible atomic rearrangements with a sharp cooperative character, involving tens to hundreds of atoms arranged in spatially extended clusters of polyhedra. Remarkably, at low temperature we observe an excess of plastically rearranging oxygen atoms which correlates with the experimental peak in the macroscopic mechanical losses. A detailed structural analysis reveals preferential connections of the irreversibly rearranging polyhedra, corresponding to edge and face sharing. These results might lead to microscopically informed design rules for reducing mechanical losses in relevant materials for structural, optical, and sensing applications.
