Diffusion on stepped surfaces III. Enhanced diffusion along step edges

The effect of enhanced jump probability in step edge (downside) rows on adsorbate diffusion was investigated by Monte Carlo simulations, for assumed attractive step adsorption and in the presence and absence of adsorbate nearest-neighbor repulsion. In all cases diffusion parallel to steps is enhanced. The effect is most pronounced at low temperatures, for NN repulsion. However, the magnitude of the enhancement is relatively small when the reduction in activation energy for jumps in ledge rows is comparable to step attraction or nearest-neighbor repulsion energies.