Correlated orientations in nanocrystal fluctuations

The dynamical behavior of small particles has been observed by high resolution electron microscopy. Spontaneous structural fluctuations, between various orientations, were observed and quantified. Clear transitions involving appearance and vanishing of twins were detected. Measurements of the angle change between succeeding configurations of the [111] atomic plane reveal the existence of several preferred angular changes. Twin related transformations give a good fit to the observed angular correlation, which excludes complete particle melting during the transition between successive configurations. It was also found that the particles rotate by a few degrees during this transformation.