The lateral growth of an isolated nucleated facet is studied using a simple two-dimensional step model. An effective Hamiltonian that causes a planar surface to phase separate into facets and step bunches is proposed. The motions of the steps are determined by the relaxational dynamics of the effective Hamiltonian with and without a local conservation requirement. An even simpler mean-field-like model is used to illustrate the mechanism of the experimentally observed constant-velocity facet tip propagation. Numerical calculations using thermodynamic and transport coefficients previously measured give good agreement with experiments under the local conservation requirement.

• Received 30 August 1996

DOI:https://doi.org/10.1103/PhysRevB.55.7653