Lattice dynamics of stishovite from powder inelastic X‐ray scattering

We have retrieved the full lattice dynamics of stishovite, SiO2, by a combination of powder inelastic x‐ray scattering (IXS) and ab initio calculations. The extracted dispersion curves are confirmed by experiments on a single crystal. Thereby we have shown that IXS powder measurements over a large range of momentum transfers allow an unambiguous validation of lattice dynamics models, which then in turn can be used to derive elastic and thermodynamic properties. The proposed method can be extended to high pressure measurements on in situ synthesized samples and promises to be a valuable tool in studies of materials for which no single crystals can be obtained.

我们通过粉末非弹性X射线散射（IXS）和从头算计算相结合的方法，获得了二氧化硅（SiO₂）斯石英的完整晶格动力学。通过对单晶的实验证实了所提取的色散曲线。因此我们表明，在大动量转移范围内进行的IXS粉末测量能够明确验证晶格动力学模型，进而可用于推导弹性和热力学性质。所提出的方法可扩展到对原位合成样品的高压测量，并有望成为研究无法获得单晶的材料的一种有价值的工具。