SURFACE STEPS AND SURFACE-MORPHOLOGY - UNDERSTANDING MACROSCOPIC PHENOMENA FROM ATOMIC OBSERVATIONS

The classical thermodynamics of surfaces is presented in terms of an atomic level picture in which steps serve as the fundamental unit. The important energy parameters which determine step behavior are defined, and their determination by experimental techniques is discussed. The connection between the relatively simple behavior of individual steps, and the complex macroscopic morphologies that are possible on surfaces is shown explicitly. The energy scales governing macroscopic morphologies are then evaluated in terms of the known energies relevant to step behavior. The well-known sensitivity of surface morphology to environment is shown to follow naturally from the understanding of step behavior. The mass transport required for transformations in surface morphology is similarly defined in terms of motion of steps. The experimental techniques which can be used to evaluate the kinetics of individual step motion and its relationship to driven mass transport are described.