INTERPLAY BETWEEN STEP VELOCITY AND MORPHOLOGY DURING THE DISSOLUTIONOF CACO3 SURFACE

The interplay between the velocity and morphology of steps during the dissolution of the-cleaved CaCO3(<10(1)over bar 4>) surface in aqueous solution has been studied using atomic force microscopy (AFM). The ex perimental results were analyzed based on the terrace-ledge-kink model . Real-time AFM images show that, in the surface reaction regime, step s not only retreat at constant velocities which depend only on the ato mic structure of the step, but also preserve a straight-edge morpholog y during the course of dissolution. The straight step morphology sugge sts that the nucleation of kinks is balanced by the annihilation of th e kinks at the step during the dissolution. This result, along with th e constant step velocity, can be explained in terms of a kink-kink ann ihilation process. (C) 1996 American Vacuum Society.