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Published October 30, 2009 | public
Journal Article

4D Nanoscale Diffraction Observed by Convergent-Beam Ultrafast Electron Microscopy


Diffraction with focused electron probes is among the most powerful tools for the study of time-averaged nanoscale structures in condensed matter. Here, we report four-dimensional (4D) nanoscale diffraction, probing specific site dynamics with 10 orders of magnitude improvement in time resolution, in convergent-beam ultrafast electron microscopy (CB-UEM). As an application, we measured the change of diffraction intensities in laser-heated crystalline silicon as a function of time and fluence. The structural dynamics (change in 7.3 ± 3.5 picoseconds), the temperatures (up to 366 kelvin), and the amplitudes of atomic vibrations (up to 0.084 angstroms) are determined for atoms strictly localized within the confined probe area (10 to 300 nanometers in diameter). We anticipate a broad range of applications for CB-UEM and its variants, especially in the studies of single particles and heterogeneous structures.

Additional Information

© 2009 American Association for the Advancement of Science. Received for publication 17 July 2009. Accepted for publication 27 August 2009. This work was supported by the NSF and the Air Force Office of Scientific Research in the Gordon and Betty Moore Center for Physical Biology at CalTech. We thank O.-H. Kwon and H. S. Park for the experimental aid in UEM-2 laboratory and acknowledge the helpful use of the Cornell TEM sample preparation facility. Caltech has filed a provisional patent application for variants of 4D microscopy.

Additional details

August 19, 2023
October 19, 2023