DISPLACEMENT DISTRIBUTION AND ATOMIC JUMP DIRECTION IN DIFFUSION OF IR ATOMS ON THE IR(001) SURFACE

On the Ir{001} surface an Ir adatom is surprisingly found to jump along the 01 direction instead of along the smoother closely packed 110 atomic channel of the substrate, probably by an atomic exchange mechanism. The sites visited by one diffusing adatom therefore form a c(2×2) net of the substrate lattice. The displacement distributions derived are consistent with those expected from a discrete random walk with the atomic jump length of the nearest-neighbor distance of the c(2×2) net. © 1990 The American Physical Society.