2014/06/30 by Tatiana Latychevskaia, Hans-Werner Fink · 8 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Advanced Electron Microscopy Techniques and Applications #Advanced X-ray Imaging Techniques #Coherent diffraction imaging #Crystallographic defect #Crystallography and Radiation Phenomena #Diffraction #Extrapolation #Graphene #Isotropy #Phase (matter) #Phase retrieval #Scattering #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/1.4906089
published in Applied Physics Letters 106(2) (American Institute of Physics) · 10 pages, 4 figures
arxiv created 2015/01/06 · openalex publication_date 2015/01/12 · arxiv updated 2015/01/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Previously reported crystalline structures obtained by an iterative phase retrieval reconstruction of their diffraction patterns seem to be free from displaying any irregularities or defects in the lattice, which appears to be unrealistic. We demonstrate here that the structure of a nanocrystal including its atomic defects can unambiguously be recovered from its diffraction pattern alone by applying a direct phase retrieval procedure not relying on prior information of the object shape. Individual point defects in the atomic lattice are clearly apparent. Conventional phase retrieval routines assume isotropic scattering. We show that when dealing with electrons, the quantitatively correct transmission function of the sample cannot be retrieved due to anisotropic, strong forward scattering specific to electrons. We summarize the conditions for this phase retrieval method and show that the diffraction pattern can be extrapolated beyond the original record to even reveal formerly not visible Bragg peaks. Such extrapolated wave field pattern leads to enhanced spatial resolution in the reconstruction.