Smoothing surfaces by an ac field: an application of the ratchet effect

摘要

We demonstrate that for surfaces that have a nonzero Schwoebel barrier, the application of an ac field parallel to the surface will induce a net electromigration current. Most important, the direction of the net current will be aloways downhill; i.e. it will point in the step-down direction. The magnitude of this equilibrium current is calculated analytically, and compared with Monte Carlo simulations. A downhill current is known to smooth the surface, thus we suggest that the application of ac fields during annealing might aid the smoothing process and during growth it has the potential to slow or eliminate the Schwoebel barrier induced mound formation.