Acquisition of high-quality three-dimensional electron diffuse scattering data

Abstract: The diffraction patterns of crystalline materials with local order contain sharp Bragg reflections as well as highly structured diffuse scattering. The instrumental requirements, experimental parameters and data processing techniques for obtaining high-quality diffuse scattering data have previously been determined for X-ray and neutron diffraction, but not yet for electron diffraction. In this study, we show that the spatial resolution of the diffuse scattering in three-dimensional electron diffraction (3D ED) data depends on various effects, including the convergence of the electron beam, the point spread function of the detector and the crystal mosaicity. In contrast to single-crystal X-ray diffraction, the detector point spread function for 3D ED is broader for a hybrid pixel detector than for a CCD. In our study, we also compare the diffuse scattering in 3D ED data with the diffuse scattering in single-crystal X-ray diffraction data and show that the diffuse scattering in 3D ED data can be obtained with a quality comparable to that from single-crystal X-ray diffraction. As electron diffraction requires much smaller crystal sizes than X-ray diffraction, this opens up the possibility to investigate the local structure of many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available.