Impact of nucleation on step-meandering instabilities during step-flow growth on vicinal surfaces

Step-meandering instabilities can manifest during step-flow growth on vicinal surfaces [Bales and Zangwill, Phys. Rev. B 41, 5500 (1990); Pierre-Louis, D'Orsogna, and Einstein, Phys. Rev. Lett. 82, 3661 (1999)]. A phase diagram based on the various growth regimes of a vicinal surface allows us to study the impact of nucleation on these meanders and to predict a meandering instability caused by the nucleation and the coalescence of both islands and steps. Using an accelerated kinetic Monte Carlo method, we find that the coalescence of islands with steps produces large protrusions and deep ripples and that the resulting meandering instability is reinforced by the growth of the islands at almost the same positions from one monolayer to the other. A coarsening phenomenon occurs for the instability wavelength until mounds appear, favored by a large Ehrlich-Schwoebel barrier. Such a meandering instability could be exploited for periodic self-assembly.