成网材料中硬度与结构序的拓扑特征
Topological Signatures of Hardness and Structural Order in Network-Forming Materials
AI总结：
该研究以成网材料为对象，引入连接价拓扑描述符，结合频谱分析，揭示了非晶与晶相二氧化硅的拓扑结构差异，为关联其结构与物理性质提供了新框架。
AI中文摘要：
理解成网材料的拓扑结构如何影响其物理性质仍是一个长期存在的挑战。本文研究了与实验兼容的非晶二氧化硅原子模型，以及晶型的方石英（cristobalite）和石英（quartz）的拓扑结构。通过比较多个同样能重现中子散射数据的非晶二氧化硅原子模型，我们发现不同的微观描述可能会对玻璃稳定性产生不同的拓扑解释。为了超越传统几何描述符来表征网络，我们引入了连接价（linking valence），它量化了每个网络环的平均拓扑连接数。该拓扑描述符将二氧化硅分为两类：尽管具有共同的四面体结构单元，机械性能更硬的石英的连接价值比非晶二氧化硅和方石英大一个数量级以上。对环连接网络的频谱分析提供了补充区分，将非晶相与晶相分离，并揭示了拓扑约束的长程组织差异。这些结果确立了拓扑连接作为连接成网材料结构与物理性质的新框架。
英文摘要：
Understanding how the topology of network forming materials influences their physical properties remains a longstanding challenge. Here, we investigate the topology of experimentally compatible atomistic models of amorphous silica together with the crystalline polymorphs cristobalite and quartz. By comparing multiple atomistic models of amorphous silica that equally reproduce neutron-scattering data, we show that different microscopic descriptions can imply different topological interpretations of glass stability. To characterize the network beyond conventional geometric descriptors, we introduce the linking valence, which quantifies the average number of topological links per network loop. This topological descriptor separates silica into two distinct classes: the mechanically harder quartz exhibit values more than an order of magnitude larger than those of amorphous silica and cristobalite, despite their common tetrahedral building blocks. Spectral analysis of the loop-linking networks provides a complementary distinction, separating amorphous from crystalline phases and revealing differences in the long-range organization of topological constraints. These results establish topological linking as a new framework for connecting the structure and physical properties of network-forming materials.
