| 研究実績の概要 |
This project contributed to the understanding of complex atomic arrangements of hypermaterials using atomic-resolution X-ray holography. This method circumvents the phase problem of traditional crystallography, thus providing unique 3-dimensional structure information in a direct manner (i.e. without the need for an a priori model or data refinement). It represents new way to visualize intricate aperiodic structures with an element-selective approach and to support existing models with complementary experimental data (in addition to e.g. superspace crystallography approaches).
The experiments using large-scale synchrotron facilities were performed for several decagonal and icosahedral quasi-crystalline systems. The data could be interpreted as 3-dimensional local pair distribution functions in the range of about 2 nm around a specific element. These features represent distinct advantages in contrast to comparable methods aimed at local structure characterization like X-ray absorption spectroscopy. It could also be demonstrated that the 3D data also indicate distinct structural features, for example the connectivity between the icosahedral clusters, which are difficult to determine by traditional crystallographic and spectroscopic approaches.
Furthermore, a new detecting system was introduced, which uses a 2-dimensional area detector. With this system, a wide variety of target elements is now feasible for measurement.
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