Atomic Resolution Study of Structural Rearrangements in Metal Clusters
Dynamic events in small particles of Au, Pt, Rh and Ru have been observed inside the electron microscope. Depending on the particle size and the beam current density, the small clusters undergo structural rearrangements, with rapid changes in orientation and shape with respect to the beam direction. Various forms of surface activity have been recorded including atom hopping, twinning and atomic "clouds" above some surfaces. In a fraction of a second, a 2.5nm ruthenium crystal changed its internal structure from cubic-close-packing to hexagonal-close-packing. Twinning was comparatively common, even in particles with diameters of 2nm or less. From hot stage observations the speed of structural rearrangements was found to be temperature dependent.
KeywordsPlatinum Hexagonal Ruthenium Rhodium
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