Landau Theory of Surface Segregation and Phase Transitions in Binary Alloys with fcc Crystal Structure

Abstract

The order-disorder transition at the surface of binary alloys with fcc structure is studied within the Landau theory. The interplay of spatial order and segregation leads to results that provide a different mechanism for the bulk first-order phase transition characteristic of these systems. The surface transition may be of first or second order. A new instability temperature towards phase separation, regulated by the surface, is obtained.