A study on the elongation of embedded Au nanoclusters in SiO2 by swift heavy ion irradiation using MD simulations

We have studied the elongation of Au nanoclusters embedded in amorphous SiO2 using MD simulations. The effect of swift heavy ions (SHI) was implemented using instantaneous energy deposition with a radial profile that was obtained from the inelastic thermal spike model. During the first impact on the cluster, the clusters (d = 9–11 nm) gained about 20% in length due to thermal stress within the cluster, which is released by a longitudinal flow of Au atoms to the ion track in silica. Our simulations also show that high temperatures at the track core lead to the formation of silica vapor, whose pressure may flatten the cluster.