  Highly ordered one-dimensional arrays of nanodots, or nanobeads, are
fabricated by forming nanoripples and nanodots in sequence, entirely by
ion-beamsputtering (IBS) of Au(001). This demonstrates the capability of IBS
for the fabrication of sophisticated nanostructures via hierarchical
self-assembly. The intricate nanobead pattern ideally serves to identify the
governing mechanisms for the pattern formation: Non-linear effects, especially
local redeposition and surface-confined transport, are essential both for the
formation and the preservation of the pattern order.
