Ordering kinetics at theCu3Au(110) surface

The evolution of ${\mathrm{Cu}}_3$Au(110) surface order from ${10}^2$ to ${10}^5$ s after disordering anneals has been monitored by low-energy electron diffraction. On the basis of refined observations of the profiles of diffracted beams, it is concluded that the early stage of surface ordering consists of the nucleation of compositionally ordered microclusters prior to bulk ordering.