  Electric dark spots are point singularities at which the electric field
amplitude vanishes. These singularities usually emerge in real space
accidentally and are unstable due to the vectorial property of the electric
field. In this paper, we show that topologically protected electric dark spots
can emerge in metal scatterers under external excitation. The material property
of metal imposes a boundary condition that reduces the vectorial electric field
on the metal surface to a scalar field. The phase singularity of this scalar
field has zero amplitude and carries a well-defined topological charge
corresponding to an electric dark spot. The topological electric dark spots
give rise to the superoscillation phenomenon with a divergent local wavenumber.
We uncover the global charge conservation property of the dark spots on the
scatterers' surfaces and demonstrate their stability under different
perturbations. We also demonstrate the manipulation of the dark spots'
topological charge and spatial location. The results open a new avenue for
nanophotonic near-field manipulations and may find applications in optical
metrology, optical sensing, and super-resolution imaging.
