  Magnetic skyrmions, which are topologically distinct magnetic spin textures,
are gaining increased attention for their unique physical properties and
potential applications in spintronic devices. Here we present a design strategy
for skyrmion host candidates based on combinations of magnetic spin, asymmetric
building units having stereo-active lone-pair electrons, and polar lattice
symmetry. To demonstrate the viability of the proposed rational design
principles, we successfully synthesized Fe(IO3)3 polycrystalline sample and
single crystals by using a new simplified low-temperature pathway, which is
experimentally feasible for extending materials growth of transition metal
iodates. Single crystal X-ray and powder synchrotron X-ray diffraction
measurements demonstrated that Fe(IO3)3 crystallizes in the polar chiral
hexagonal lattice with space group P63. The combined structural features of the
macroscopic electric polarization along the c axis stemming from the
coalignment of the stereo-active lone-pairs of the IO3 trigonal pyramid and the
magnetic Fe3+cation residing on the three-fold rotation axis were selected to
promote asymmetric exchange coupling. We find evidence of a predicted skyrmion
phase at 14 K to 16 K and 2.5 T to 3.2 T driven by Dzyaloshinskii Moriya (DM)
interaction, a conclusion supported by the appreciable DM exchange and the
zero-field spiral antiferromagnetic ground state of Fe(IO3)3 deduced from
neutron diffraction experiments. The associated magnetic modulation wavelength
of the putative skyrmions is expected to be short, approximately 18 nm,
comparable to the period of the DM-driven incommensurate order. This work links
stereo-active lone-pair electron effects to enhanced DM interaction,
demonstrating a new approach for chemical guidelines in the search for
skyrmionic states of matter.
