Elastic effects on surface physics

The importance of stress and strain effects on surface physics are reviewed. For this purpose the following points are developed. (1) The elastic, thermodynamics and atomistic definitions of surface stress and surface strain are presented in a complementary way so that the surface stress and surface strain concepts based on a proper definition of surface elastic energy in terms of excess quantities are presented in depth. This leads to a natural link between surface stress and surface energy known as Shuttleworth’s relation. (2) The elastic description of surface defects as adatoms, steps, undulation, 2D and 3D islands are reviewed in the framework of elastic point forces concept then partially discussed in terms of forces distribution. (3) As an application, thermodynamics and kinetics description of elastic driven instabilities are reviewed with a particular emphasis on spontaneous Asaro–Tiller–Grienfeld morphological instability, Stranski–Krastanov transition and Marchenko–Andreev domains formation. Some examples are thus described and discussed for pure material as well as for alloys. (4) In case of vicinal faces, step bunching and step meandering instabilities driven by elasticity are rationalised and discussed in a quite complementary way. In particular it is shown how step–step interaction and/or step–adatom interaction may lead to kinetics instabilities. (5) Strain effects on diffusion are discussed. (6) Elasticity effect on some surface phase transition as surface melting or surface roughening are discussed in quite simple model. In case of surface melting of epitaxial layers, new phenomenon as boosted premelting is then predicted. (7) Experimental examples of elasticity as a tool for self-organisation are thus presented.