Nanoscale Pt particles, situated on a Pt surface, were studied by means of molecular dynamics simulations. It was shown that, for the simple case of symmetrical twist boundaries with low-index planes, the structure and dynamics of the system were sensitive to finite-size effects. Thus, when below a certain size, the particles aligned themselves with the substrate. In the case of larger particles, a stable array of grain boundary dislocations was created. Nanoparticle rotation was a direct result of athermal slip of the grain boundary dislocations which were created at the particle/substrate interface. The size effects were limited to nano-sized particles, and therefore had not yet been observed in experiments. The simulations also showed that the energy and structure of the boundaries were affected by the system size.

Nanocluster Rotation on Pt Surfaces - Twist Boundaries. Y.Ashkenazy, R.S.Averback, K.Albe: Physical Review B, 2001, 64[20], 205409 (9pp)