Diffusion of gold nanoclusters on graphite

Abstract

We present a detailed molecular-dynamics study of the diffusion and coalescence of large (249-atom) gold clusters on graphite surfaces. The diffusivity of monoclusters is found to be comparable to that for single adatoms. Likewise, and even more important, cluster dimers are also found to diffuse at a rate which is comparable to that for adatoms and monoclusters. As a consequence, large islands formed by cluster aggregation are also expected to be mobile. Using kinetic Monte Carlo simulations, and assuming a proper scaling law for the dependence on size of the diffusivity of large clusters, we find that islands consisting of as many as 100 monoclusters should exhibit significant mobility. This result has profound implications for the morphology of cluster-assembled materials.

Study of Friction of Ag and Ni Nanoparticles: An Atomistic Approach

“…33 In Refs. [12][13][14] it was found that small nanoparticles (with up to several hundreds atoms) are very mobile in the temperature range 300-900 K and diffuse easily on a graphite surface. Moreover, in Ref.…”

“…28 Therefore, our approach is a good starting point which should provide a qualitatively correct but not quantitatively precise description of the system which should be relevant for metal nanoparticles that weekly bind with graphene. 13 The simulation code is implemented using NVIDIA CUDA TM platform 30,31 which allowed us to carry out the computations on a single graphics processing unit (GPU) NVIDIA GeForce TM GTX 260. Algorithms for GPU based on the neighbor-list technique from Ref.…”

“…[12][13][14] Such small systems are not appropriate for the study of tribological properties and nanoparticles of several orders of magnitude larger should be inspected.…”

Nucleation and Aggregative Growth of Palladium Nanoparticles on Carbon Electrodes: Experiment and Kinetic Model

“…26,45 Furthermore, surface diffusion on a substrate can occur thermally 46 and due to electrochemically 47,48 induced migration. This process is thus reasonably consistent with the TEM data and electrochemical measurements.…”

Misfit-dislocation-mediated heteroepitaxial island diffusion

“…They have also been shown to relieve stress in strained films, greatly affecting the growth mode [2][3][4], and have been predicted [5,6] but never experimentally implicated in thermally activated surface diffusion of atom clusters. Instead, experimental studies of island diffusion have been mostly limited to homoepitaxial systems where island motion is a result of atomic diffusion events at steps [7][8][9][10][11], with collective cluster motion being negligible for groups of atoms of more than a few, with rare exceptions [12][13][14]. This work is at the confluence of bulk and surface phenomena by demonstrating that dislocations allow the movement of clusters by reducing the barrier for motion in the same way that they reduce the yield stress of bulk materials: by enabling slip to occur in a piecewise fashion.…”