Molecular dynamics simulations were made of adatom descent, from straight steps on (111), by using many-body tight-binding potentials. It was found that such descent could occur by jumping or exchange. The static energy barriers were very similar for both mechanisms, and were much higher than the barrier for return to the inner terrace. However, simulations for temperatures of 450 to 650K showed that adatoms exchanged rapidly, and jumps were rare at both steps. The results suggested that the Schwoebel barrier to exchange decreased at high temperatures.

R.Ferrando, G.Tréglia: Physical Review Letters, 1996, 76[12], 2109-12