Three-Dimensional Imaging of Microstructure in Au Nanocrystals

X-ray diffraction using a coherent beam involves the mutual interference among all the extremities of small crystals. The continuous diffraction pattern so produced can be phased because it can be oversampled. We have thus obtained three-dimensional images of the interiors of Au nanocrystals that show 50 nm wide bands of contrast with $\{111\}$ orientation that probably arise from internal twinning by dynamic recrystallization during their formation at high temperature.