Antiferromagnetic Skyrmions and Skyrmion Density Wave in Rashba Hund’s Insulator.

We discover magnetic phases hosting highly elusive and technologically important antiferromagnetic skyrmion quasiparticles in a model for Rashba-coupled Hund’s insulator. The results are based on unbiased simulations of a classical super-exchange model derived, in this work, from a realistic microscopic electronic Hamiltonian. We also discover a novel skyrmion density wave ground state characterized by a (Q, Q) modulation in the local skyrmion density map. A unique inhomogeneous state characterized by a circular pattern in spin structure factor and filamentary real-space textures is identified as the parent of sparse antiferromagnetic skyrmions. We predict that the magnetic states reported here can be realized in thin films of multiorbital systems involving 4d or 5d transition metals.