Subsurface ordering kinetics at Cu ₃ Au(001)

Abstract

The peculiar two-step ordering kinetics, discovered recently in time-resolved X-ray experiments on the Cu3Au(001) surface after a temperature quench to the ordered phase is analyzed within the time-dependent Ginzburg-Landau theory. Our model accounts for both the fast propagation of an ordering wave into the bulk, initiated by Au-surface segregation, and a time-delayed propagation of lateral order from the bulk to the surface. We also discuss further effects predicted by our theory, like the appearance of a characteristic penetration depth of the ordering wave and a secondary relaxation in its amplitude, which have not yet been detected experimentally.

Metastable vs. unstable growth in the subsurface ordering dynamics of Cu 3 Au (001)

“…Previous studies of the ordering kinetics at the Cu 3 Au(001) surface have concentrated on the time evolution of the average local order ("q = 0") unravelling a fast temporal evolution of the average Ψ 3 component in the subsurface region [11]. This is the signature of a highly anisotropic growth process in the subsurface region [12].…”