Understanding Fivefold Symmetry in Electron-Diffraction Patterns

摘要: Electron-diffraction patterns with 5-fold rotational symmetry of experimental alloy phases are assumed to be produced by periodic structures. Two three-dimensional periodic structures are presented based on  regular pentagonal dodecahedrons. These structures can be used as atomic models to describe the alloy phases. The Fourier-transform patterns of the models are found to be similar to the corresponding electron-diffraction patterns of these alloy phases. Details of the motivations and approaches that lead to these models are also discussed.