6533b85cfe1ef96bd12bc832

RESEARCH PRODUCT

Chapter III Phase transitions at surfaces

subject

description

Abstract The statistical mechanics of phase transitions is briefly reviewed, with an emphasis on surfaces. Flat surfaces of crystals may act as a substrate for adsorption of two-dimensional (d=2) monolayers and multilayers, offering thus the possibility to study phase transitions in restricted dimensionality. Critical phenomena for special universality classes can thus be investigated which have no counterpart in d=3. Also phase transitions can occur that are in a sense “in between” different dimensionalities (e.g., multilayer adsorption and wetting phenomena are transitions in between two and three dimensions, while adsorption of monolayers on stepped surfaces allows phenomena in between one and two dimensions to be observed). Related phenomena concern transitions of surface layers of semi-infinite bulk systems: such singularities of a surface excess free energy may be related to a bulk transition (e.g., surface-induced ordering or disordering, surface melting, etc.) or may be a purely interfacial phenomenon (e.g. the roughening and facetting transitions of crystal surfaces). This article gives an introductory survey of these phenomena, discussing also illustrative model calculations employing computer simulation techniques.