基于铪基非晶光学涂层的网络拓扑：掠入射X射线全散射与原子建模研究
Network Topology of Hafnia-Based Amorphous Optical Coatings by Grazing-Incidence X-ray Total Scattering and Atomic Modeling
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中文总结 AI 辅助
该研究结合掠入射X射线全散射与原子建模，揭示了SiO₂掺杂及退火对非晶HfO₂基光学涂层原子网络拓扑的改性机制，为理解其机械损耗行为提供了原子尺度依据。
中文摘要 AI 辅助
非晶氧化铪基薄膜是用于低温引力波（GW）探测器的极具潜力的光学涂层材料，但其性能取决于掺杂和退火处理对原子网络的改性方式。我们结合掠入射X射线全散射测量与实验约束原子建模，研究了沉积态HfO₂以及27% SiO₂掺杂的HfO₂薄膜在150℃和400℃退火后的结构。纯非晶HfO₂是以Hf为中心的多面体构成的致密高配位网络，具有大量边共享和面共享连接。引入SiO₂会生成稳定的SiO₄四面体，降低Hf和O的配位数，并用混合Si-O-Hf桥接取代高连接性的富Hf氧环境，形成化学混合网络而非孤立的富SiO₂区域，同时使阳离子拓扑向角共享连接转变。400℃退火仅产生适度的额外结构弛豫。这些结果提供了SiO₂改性非晶HfO₂基涂层拓扑的原子尺度描述，并提出了与理解其机械损耗行为相关的结构描述符。
英文摘要
Amorphous hafnia-based films are promising optical-coating materials for cryogenic GW detectors, but their performance depends on how doping and annealing modify the atomic network. We combine grazing-incidence X-ray total scattering measurements with experimentally constrained atomic modeling to study the as-deposited HfO$_2$ and 27% SiO$_2$-doped HfO$_2$ films annealed at 150$^\circ$C and 400$^\circ$C. Pure amorphous HfO$_2$ is a dense, high-coordination network of Hf-centered polyhedra with substantial edge- and face-sharing connectivity. Incorporating SiO$_2$ introduces stable SiO$_4$ tetrahedra, lowers the Hf and O coordination, and replaces highly connected Hf-rich oxygen environments with mixed Si--O--Hf bridges. This produces a chemically mixed network rather than isolated SiO$_2$-rich regions, and shifts the cation topology toward corner-sharing connectivity. Annealing to 400$^\circ$C produces only modest additional structural relaxation. These results provide an atomic-scale description of how SiO$_2$ modifies the topology of amorphous HfO$_2$-based coatings and suggest structural descriptors relevant to understanding their mechanical-loss behavior.
