0000000000445093
AUTHOR
Werner Schweika
Continuous Phase Transitions at Surfaces of CuAu Alloy Models — A Monte Carlo Study of Surface Induced Order and Disorder
The influence of surface on phase transitions has found significant attention in recent years, and a number of excellent reviews exists. [1, 2, 3] A variety of complex phenomena occur which are also related to the physics of adsorption and wetting. The scenario of wetting requires three distinct phases, for instance the vacuum, the bulk phase and a third phase intervening in between at equilibrium. In case of surface induced disorder (SID, a film of disordered layers at the surface “wets” the bulk phase as the temperature approaches the bulk transition temperature T c,b. The transition at the surface may be continuous (standard critical wetting phenomena), and, as theoretically investigated…
Surface-induced ordering and disordering in face-centered-cubic alloys: A Monte Carlo study
Using extensive Monte Carlo simulations we have studied phase transitions in a fcc model with antiferromagnetic nearest-neighbor couplings $J$ in the presence of different free surfaces which lead either to surface-induced order or to surface-induced disorder. Our model is a prototype for CuAu-type ordering alloys and shows a strong first-order bulk transition at a temperature $\frac{k{T}_{\mathrm{cb}}}{|J|}=1.738005(50)$. For free (100) surfaces, we find a continuous surface transition at a temperature ${T}_{\mathrm{cs}}g{T}_{\mathrm{cb}}$ exhibiting critical exponents of the two-dimensional Ising model. Surface-induced ordering occurs as the temperature approaches ${T}_{\mathrm{cb}}$ and …