Instabilities and reconstructions on solid surfaces: basic theoretical notions and examples

The phenomenon of crystal surface instability and reconstruction is considered. Peculiarities of the surface electronic structure and the chemical bonding at the surface are discussed from this point of view. Various criteria and theories, both microscopic and phenomenological, are presented, which may be helpful in elucidating the problem. The emphasis is laid on simple ideas and the concepts introduced are illustrated with examples from the field of surface physics. The reconstruction of the W and Mo(001) surface, fcc metal surfaces and of the silicon surfaces are reviewed in considerable detail and a comparison with the experimentally established facts is made.