Resonant X-ray Diffraction under optimized destructive interference for highly sensitive determination of phase-resolved site-selective atomic displacements in crystalline materials

该项目旨在系统地增强共振x射线衍射，以实现高灵敏度，相位分辨晶体理想结构内原子位移的测定。这些原子位置的偏差将在低维系统中以及在温度、机械应力以及电场和磁场等外部影响下表现出来。通过改变入射x射线光子的能量来调谐到最大的相消干涉，从而获得了灵敏度的本质提高。该方法将被选定的三元和四元氧化物验证，这是目前研究的主要焦点。理论第一原理建模将支持对实验确定的偏差的解释，并确保物理化学的结论。在晶体结构中的相分辨原子位移方面，一种具有极高精度的实验表征方法有望从这个项目中得到。

The project aims at the methodical enhancement of Resonant X-ray Diffraction towards highly sensitive, phase-resolved determination of atomic displacements within the ideal structure of a crystal. These deviations of atomic positions will be characterized both in low-dimensional systems and under external influences like temperature, mechanical stress as well as electric and magnetic fields. Tuning to maximal destructive interference by means of varying the incident X-ray photon energy attains the essential increase of sensitivity. The method will be verified for selected ternary and quaternary oxides, which are in prime focus of current research. Theoretical first-principle modelling will support the interpretation of the experimentally determined deviations and ensure physio-chemical conclusiveness. An experimental characterization method with extreme accuracy in terms of phase-resolved atomic displacements in crystalline structures is expected from this project.