X-ray cross correlation analysis uncovers hidden local symmetries in disordered matter

作者：Wochner Peter; Gutt Christian; Autenrieth Tina; Demmer Thomas; Bugaev Volodymyr; Ortiz Alejandro Diaz; Duri Agnes; Zontone Federico; Gruebel Gerhard; Dosch Helmut^*

来源：Proceedings of the National Academy of Sciences, 2009, 106(28): 11511-11514.

DOI：10.1073/pnas.0905337106

• coherent X-ray diffraction
• higher-order correlations
• structure

We explore the different local symmetries in colloidal glasses beyond the standard pair correlation analysis. Using our newly developed X-ray cross correlation analysis (XCCA) concept together with brilliant coherent X-ray sources, we have been able to access and classify the otherwise hidden local order within disorder. The emerging local symmetries are coupled to distinct momentum transfer (Q) values, which do not coincide with the maxima of the amorphous structure factor. Four-, 6-, 10- and, most prevalently, 5-fold symmetries are observed. The observation of dynamical evolution of these symmetries forms a connection to dynamical heterogeneities in glasses, which is far beyond conventional diffraction analysis. The XCCA concept opens up a fascinating view into the world of disorder and will definitely allow, with the advent of free electron X-ray lasers, an accurate and systematic experimental characterization of the structure of the liquid and glass states.

• 出版日期2009-7-14
• 单位中国科学院金属研究所