Dissolution–precipitation recrystallization of miscut crystal surfaces under stress

We studied the coarsening evolution of step patterns on sodium chlorate miscut surfaces due to recrystallization under compressive stress in a saturated solution. The coarsening rates and pattern geometries were measured by digital image analyses of optical microscopy recordings. The average distance between the macrosteps (λ) initially grew according to λ∼t1/4, but changed to λ∼t1/2 later in the experiments. The relatively rapid transition in coarsening rate was not accompanied by a sudden transition in pattern geometry, characterized by the number of step intersection points and terrace aspect ratios. The mean terrace aspect ratio continuously decreased, due to a gradual transition from relatively straight (perpendicular to principal stress) to more undulating steps. Possible causes of the observed transition in pattern evolution are: (i) a reduction of step line tension; (ii) an increasing variation in the surface stress distribution; and/or (iii) a change in growth morphology of sodium chlorate due to a decreasing driving force (supersaturation) of recrystallization.