Surface stress of clean and adsorbate-covered solids

Starting with a simple introduction into the phenomenon of surface stress from a thermodynamic as well as from an atomistic viewpoint, the currently available literature on surface stress of clean and adsorbate-covered surfaces is reviewed. The equations which are used to calculate the adsorbate-induced changes of the surface stress tensor from cantilever bending experiments are derived and their limitations are discussed. It is shown for several examples that charge transfer effects have a pronounced influence on the adsorbate-induced surface stress. The linear relation between surface stress and surface charge which has been observed experimentally at the metal-electrolyte interface is rationalized in the framework of thermodynamics. The role of surface stress as a driving force for surface reconstruction and for the structural organization of surfaces on a mesoscopic scale are discussed for a few selected examples. Novel applications of surface stress effects for sensor and actuator applications are described.