2020 Fiscal Year Research-status Report
Accurate site-selective atomic structure determination by single-energy x-ray holography
| Project/Area Number |
20K15027
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| Research Institution | Hiroshima University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | site-selectivity / x-ray holography / atomic structure / local atomic environment |
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| Outline of Annual Research Achievements |
The aim of this project is to implement site-selective investigations in X-ray holography. These are useful for, among else, identifying local atomic environments with chemical information and for understanding in detail the chemical disorder. This is achieved by exploiting resonant effects (i.e. tuning the X-ray energy to an energy that coincides with an X-ray absorption edge in the material). One of the obstacles here is the atomic image cancellation effect. The consequences of this effect were mapped in this first part of the project by using computationally simulated data as well as available experimental data. Also, first steps were taken to address numeric solutions for such single-energy based holography approaches.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The first step of the project was concerned with establishing the background and the characterization of the interdependence of the significant parameters, which was successfully achieved.
The experimental plan was slightly delayed (synchrotron experiments delayed due to the pandemic situation), but previously available experimental data could be used, combined with model data from computer simulations, which supported the advancement of the project.
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| Strategy for Future Research Activity |
The next step of the project is targeted at systems for which conventional X-ray holography data are already well established, but are still subject to discussion in current material science, e.g. Mn doped Bi2Te3, which is of scientific and technological interest as a topological insulator. Previous experiments have found two possible sites for the Mn atom, in which the type of the neighboring atoms (Bi or Te) could not be identified. This can be clarified by this project. After that, the next step will be the application to more complex systems.
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| Causes of Carryover |
The budget set aside to present the research at international conferences could not be used appropriately in FY2020 due to postponement of most major conferences. It will be used in FY2021 for the same purpose.
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