Zaug Joseph M, Soper Alan K, Clark Simon M
Chemistry Materials Energy and Life Sciences, Lawrence Livermore National Laboratory, 7000 E. Avenue, L-350, Livermore, California 94551, USA.
Nat Mater. 2008 Nov;7(11):890-9. doi: 10.1038/nmat2290. Epub 2008 Oct 12.
Characterizing the nature of medium-range order (MRO) in liquids and disordered solids is important for understanding their structure and transport properties. However, accurately portraying MRO, as manifested by the first sharp diffraction peak (FSDP) in neutron and X-ray scattering measurements, has remained elusive for more than 80 years. Here, using X-ray diffraction of amorphous red phosphorus compressed to 6.30 GPa, supplemented with micro-Raman scattering studies, we build three-dimensional structural models consistent with the diffraction data. We discover that the pressure dependence of the FSDP intensity and line position can be quantitatively accounted for by a characteristic void distribution function, defined in terms of average void size, void spacing and void density. This work provides a template to unambiguously interpret atomic and void-space MRO across a broad range of technologically promising network-forming materials.
表征液体和无序固体中的中程有序（MRO）性质对于理解它们的结构和传输特性至关重要。然而，80多年来，准确描绘由中子和X射线散射测量中的第一尖锐衍射峰（FSDP）所体现的MRO一直难以实现。在这里，我们利用压缩至6.30 GPa的非晶态红磷的X射线衍射，并辅以显微拉曼散射研究，构建了与衍射数据一致的三维结构模型。我们发现，FSDP强度和谱线位置的压力依赖性可以通过一个特征性的空隙分布函数来定量解释，该函数根据平均空隙尺寸、空隙间距和空隙密度来定义。这项工作提供了一个模板，用于明确解释广泛的具有技术前景的网络形成材料中的原子和空隙空间MRO。
