Competing mechanisms in adatom diffusion on a channeled surface: Jumps versus metastable walks

It is shown, by molecular-dynamics simulations, that in-channel Au adatom diffusion on missing-row reconstructed Au(110) takes place by two different mechanisms, jumps and metastable walks. In a metastable walk the adatom climbs up one of the (111) facets of the channel, diffuses fast along the network of metastable minima an that facet, and finally is trapped again at the channel bottom. A considerable fraction of the events giving direct mass transport to distant cells occurs by this new mechanism.