The stability of growing or evaporating crystals

The linear stability of a Stefan-like problem for moving steps is analyzed within the context of Burton, Cabrera, and Frank's theory of crystal growth [Philos. Trans. R. Soc. London Ser. A 243, 299 (1951)]. Asymmetry and departures from equilibrium at steps are included. The equations for regular perturbations around the steady state are solved analytically. The stability criterion depends on supersaturation and average step spacing, both experimentally accessible, and on dimensionless combinations of surface diffusivity, surface diffusion length, and adatom capture probabilities at steps, which can be estimated from bond models. This stability criterion is analyzed and presented graphically in terms of these physical parameters.