  Atomic force microscopy (AFM) nanomanipulation has been viewed as a
deterministic method for the assembly of plasmonic metamolecules because it
enables unprecedented engineering of clusters with exquisite control over
particle number and geometry. Nevertheless, the dimensionality of plasmonic
metamolecules via AFM nanomanipulation is limited to 2D, so as to restrict the
design space of available artificial electromagnetisms. Here, we show that 2D
nanomanipulation of the AFM tip can be used to assemble 3D plasmonic
metamolecules in a versatile and deterministic way by dribbling highly
spherical and smooth gold nanospheres (NSs) on a nanohole template rather than
on a flat surface. Various 3D plasmonic clusters with controlled symmetry were
successfully assembled with nanometer precision, the relevant 3D plasmonic
modes (i.e., artificial magnetism and magnetic-based Fano resonance) were fully
rationalized by both numerical calculation and dark-field spectroscopy. This
templating strategy for advancing AFM nanomanipulation can be generalized to
exploit the fundamental understanding of various electromagnetic 3D couplings
and can serve as the basis for the design of metamolecules, metafluids, and
metamaterials.
