The solid-on-solid kinetic Monte Carlo model of Lasaga & Blum (1986) for dislocation-controlled etch-pit growth was extended to the growth of etch pits under the control of multiple dislocations and point defects. This required the development of algorithms that were 103 to 104 times faster than primitive kinetic Monte Carlo models for surfaces with areas in the range of 1024 x 1024 to 4096 x 4096 lattice sites. Simulations with multiple line defects indicated that the surface morphology coarsens with increasing time and that the coarsening was more pronounced for large bond-breaking activation energies. For small bond breaking activation energies dissolution enhanced by line defects perpendicular to the dissolving surface results in pits with steep sides terminated by deep narrow hollow tubes (nanopipes). Larger bond breaking activation energies led to shallow pits without deep nanopipes, and if the bond breaking activation energy was large enough, step flow was the primary dissolution mechanism, and pit formation was suppressed. Simplified models that neglected the far field strain energy density but included either a rapidly dissolving core or an initially empty core led to results that were qualitatively similar to those obtained using models that included the effects of the far field stress and strain. Simulations with a regular array of line defects show that microscopic random thermal fluctuations played an important role in the coarsening process.

Simple Kinetic Monte Carlo Models for Dissolution Pitting Induced by Crystal Defects. P.Meakin, K.M.Rosso: Journal of Chemical Physics, 2008, 129[20], 204106