Kink dynamics and step growth on barium sulfate (001): A hydrothermal scanning probe microscopy study

We have measured step growth kinetics on barium sulfate (001) as a function of step length, supersaturation, and temperature. rising a one-dimensional nucleation model, we report kink detachment coefficients for [120] monolay er steps of w- = 114 (+/-14), 187 (+/-17), and 357 (+/-43) s(-1), at 90, 10 8, and 125 degrees C, respectively, giving an activation energy, E-a = 0.39 (+/- 0.05) eV. The kink formation energy, epsilon, was found to be 0.16 (/-0.02) eV. The uncertainty in this energy is sufficient to envelop the exp erimentally determined kink densities, but the lack of increase in experime ntal kink density with increase in temperature points to kinetic limitation s in the experiments. Due to the kinetic limitations of growth at kinks whe ther they are from diffusion or attachment, our results demonstrate that kn owledge of the kink kinetics as a function of temperature is important in t esting the applicability of the classical thermodynamic model to kinetic da ta.