Instability in molecular beam epitaxy due to fast edge diffusion and corner diffusion barriers

Fast edge diffusion leads to a diffusion bias during molecular beam epitaxy. Kinetic Monte Carlo simulations on a solid-on-solid model incorporating fast edge diffusion clearly show pattern formation. Fast edge diffusion combined with an excess barrier to go past the outer corner of an island results in wavy steps, similar to the Bales-Zangwill instability, in the step flow growth regime. The evolution of surface morphology with fast edge diffusion and corner diffusion barriers is discussed in terms of the surface diffusion current.