Step‐Energy Barriers and Particle Shape Changes during Coarsening

Abstract

Models of particle shape changes usually do not account for the step‐energy barrier associated with adding or removing additional atomic planes from a faceted surface. However, the step‐energy barrier can be a substantial limitation when the free energy changes that drive particle shape changes are relatively low. A good example of this is particle coarsening. The analysis presented in this article describes dislocation‐free particles with surfaces that have faceted and nonfaceted regions. When the chemical potential differences responsible for shape changes are too small to overcome the step‐energy barrier, atomic layers cannot be added or removed from the facets. Even with this constraint, it is possible to add or remove atoms from the particle surface; however, this can cause the particle shape to differ substantially from the traditional equilibrium shape.