Kinetic surface segregation and the evolution of nanostructures

As nonplanar structures evolve via surface diffusion, the difference in diffusivity of the alloy components leads to kinetic surface segregation. This drastically affects the rate of shape evolution, and for nanoscale structures, also the final composition distribution. This is illustrated for a classic problem, the smoothing of a surface ripple. In contrast to the single-component case, alloy evolution is generally faster during growth than during annealing. Moreover, evolution at the nanoscale is generally faster than expected from extrapolation of macroscopic behavior. (C) 2003 American Institute of Physics.