Nature of multilayer steps on the ?100? cleavage planes of MgO single crystals

The results of an AFM study of the nature of multilayer steps on the {100} cleavage faces of MgO crystals is described and discussed. The results show that (i) multilayer cleavage steps of a width between 55 and 590 nm and of a slope between about 1 and 8° are stable, (ii) the terminal planes of multilayer steps are composed of high-index vicinal faces with indices (7 0 1), (42 0 1) and (77 0 1) for the <010> steps with respect to the (100) cleavage, which do not correspond to the low-index planes of the equilibrium form of MgO crystals, and (iii) that the curved parts of the profile of a multilayer cleavage step in its upper and lower regions extend to a distance equal to the width of the step.