Temperature-dependent interfacial stiffness of the disorder layer in a thin Cu3Au alloy film

Abstract

The order-disorder transition in a 170 Å thick Cu3 Au(111) epitaxial alloy film is examined using x-ray diffraction techniques. Below the transition temperature T0, a disordered surface layer of thickness l is detected. This layer exhibits wetting behavior, i.e., l increases, obeying a logarithmic growth law on approach to T0. We show by a detailed analysis of the order parameter profiles that the stiffness of the order-disorder interface is temperature dependent, resulting in a nonuniversality of the wetting transition. © 2000 The American Physical Society.