LONG JUMPS IN SURFACE-DIFFUSION - ONE-DIMENSIONAL MIGRATION OF ISOLATED ADATOMS

Diffusion of individual metal atoms on a metal is usually viewed as a random walk between adjacent sites. We have now examined the actual jump processes participating in atomic migration by measuring the distribution of displacements for a single atom of tungsten as well as of palladium on W(211), on which diffusion is one dimensional. In the self-diffusion of a tungsten adatom, only jumps between nearest-neighbor sites contribute. For relatively weakly bound Pd atoms, however, significant contributions from jumps spanning two as well as three nearest-neighbor distances have been identified. © 1995 The American Physical Society.