High-temperature study of the Schwoebel effect in Au(111)

Quantitative measurement of the surface self-diffusion on Au nanoparticles by aberration-corrected transmission electron microscopy

We present a method that allows for a quantitative measurement of the surface self-diffusion on nanostructures, such as nanoparticles, at the atomic scale using aberration-corrected high-resolution transmission electron microscopy (HRTEM). The diffusion coefficient can be estimated by measuring the fluctuation of the atom column occupation at the surface of Au nanoparticles, which is directly observable in temporal sequences of HRTEM images. Both a Au icosahedron and a truncated Au octahedron are investigated, and their diffusion coefficients are found to be in the same order of magnitude, D = 10(-17) to 10(-16) cm(2)/s. It is to be assumed that the measured surface diffusion is affected by the imaging electron beam. This assumption is supported by the observed instability of a (5 × 1) surface reconstruction on a {100} Au facet.

Local electromigration model for crystal surfaces

The dynamics of crystal surfaces in the presence of electromigration is analyzed. From a phase field model with a migration force which depends on the local geometry, a step model with additional contributions is derived in the kinetic boundary conditions. These contributions trigger various surface instabilities, such as step meandering, bunching, and pairing on vicinal surfaces. Experiments are discussed.

Mesoscopic relaxation in homoepitaxial metal growth

We demonstrate that a size-dependent mesoscopic mismatch exists in homoepitaxy, which has a strong impact on the morphology of the islands and the substrate. Atomic scale calculations for double layer Cu islands on Cu(111) reveal that mesoscopic strain relaxations in both islands and the substrate strongly influence the shape of islands and can effect the details of atomic motion near the island.