We study the pattern evolution of pre-rippled Au͑001͒ during sputtering by an ion beam that is incident perpendicular to the initial ripple in azimuth at a grazing angle. Prepatterned ripples decay exponentially with time and new ripples develop only after extended flat areas form along the crossing-ion beams. Hence, the superposition of the initial and new ripple patterns does not occur. The kinetic behaviors of new ripples growing on pre-rippled Au͑001͒ by the crossing-ion beams are distinct from those on initially flat Au͑001͒. When comparing the pre-rippled surface to the initially flat surface, the morphological evolution is substantially influenced by enhanced nonlinear effects such as redeposition.

Molecular dynamics investigation of interfacial mixing behavior in transition metals (Fe, Co, Ni)-Al multilayer system J. Appl. Phys. 105, 034902 (2009); 10.1063/1.3073899The rotation of ripple pattern and the shape of the collision cascade in ion sputtered thin metal films J. Appl. Phys.Surface structure evolution during atomic deposition in a Co-Al system was investigated using coaxial impact collision ion scattering spectroscopy ͑CAICISS͒. Half monolayer of Al and Co atoms were deposited on Co͑0001͒ and Al͑001͒ single crystal surfaces, respectively, in an ultrahigh-vacuum environment. CAICISS analysis of the deposited surface revealed an asymmetric interfacial reaction, as predicted by previous molecular dynamics simulations. Al atoms deposited on a Co substrate are placed on the surface with no interatomic intermixing. In contrast, significant surface intermixing with the deposited Co atoms occurs on the Al͑001͒ substrate, resulting in the formation of a CoAl intermetallic surface layer of B2 structure. These asymmetric features would be important to the understanding of the structural evolution of thin film multilayers.

Deposition and annealing behaviors of Al atoms on rough Cu ͑111͒ surface were investigated on the atomic scale by three-dimensional classical molecular dynamics simulation. The rough Cu surface was modeled by depositing 5 ML of Cu on Ta ͑011͒ substrate. Most Al atoms deposited on the rough Cu surface placed on the atomic steps, preserving the major features of the surface during Al deposition. This behavior was discussed in terms of the smaller barrier of the surface diffusion than Ehrlich-Schwoebel barrier of Al on Cu ͑111͒ surface. By annealing at 700 K, significant intermixing between Al and Cu rapidly occurs with decrease in the surface roughness. This behavior reveals that the exchange process of Al with substrate Cu dominates during the initial stage of high temperature annealing.