Landau theory of second-order phase transitions on solid surfaces

Abstract

A unified description of structural transformations on solid surfaces, within the Landau theory of phase transitions, is given. We present a brief review of experimental data on surface reconstruction and surface phase transitions which enable us to illustrate the application of the Landau theory of second-order phase transitions to surface problems. The basic ideas and approximations of the Landau theory are surveyed. The Landau-Lifshitz conditions restricting the possible symmetry changes in second-order phase transitions are discussed. A review of theoretical works on application of the Landau theory to 2D and 3D systems is presented. We discuss the possibility of the description of surface layer symmetry by the 80 diperiodic groups in three dimensions. The group theoretical approach, within the Landau theory, is presented to predict the possible symmetry changes in second-order phase transitions in diperiodic 3D systems. A comparison with the results for 2D and 3D systems as well as with experimental data is given.