It was demonstrated that, for surfaces having a non-zero Schwoebel barrier, the application of an alternating-current field parallel to the surface introduced a net electromigration current that pointed in the descending step direction. The magnitude of this current was calculated analytically, and was compared with Monte Carlo simulations. Because a down-hill current tended to smooth the surface, the present results implied that the application of alternating-current fields could aid smoothing during annealing, and could slow or eliminate Schwoebel barrier-induced mound formation during growth.

Ratchet Effect in Surface Electromigration: Smoothing Surfaces by an AC Field I.Derényi, C.Lee, A.L.Barabási: Physical Review Letters, 1998, 80[7], 1473-6