Coupled Skyrmion Sublattices inCu2OSeO3

Abstract

We report the observation of a Skyrmion lattice in the chiral multiferroic insulator ${\mathrm{Cu}}_2{\mathrm{OSeO}}_3$ using Cu $L_3$-edge resonant soft x-ray diffraction. We observe the unexpected existence of two distinct Skyrmion sublattices that arise from inequivalent Cu sites with chemically identical coordination numbers but different magnetically active orbitals. The Skyrmion sublattices are rotated with respect to each other, implying a long wavelength modulation of the lattice. The modulation vector is controlled with an applied magnetic field, associating this moirélike phase with a continuous phase transition. Our findings will open up a new class of science involving manipulation of quantum topological states.