Steps on surfaces: experiment and theory

The properties of steps in thermal equilibrium are described in the context of prediction of the stability and evolution of nanostructures on surfaces. Experimental techniques for measuring the appropriate step parameters are described, and simple lattice models for interpreting the observations are reviewed. The concept of the step chemical potential and its application to the prediction of step motion (and therefore surface mass transport) is presented in depth. Examples of the application of this step-continuum approach to experimental observations of evolution of surface morphology are presented for morphological phase transitions, the decay of metastable structures, and the spontaneous evolution of metastable structure due to kinetic instabilities.