Antiferromagnetic Skyrmions and Skyrmion Density Wave in Rashba Hund's Insulator

TL;DR

This paper reports the discovery of antiferromagnetic skyrmions and a novel skyrmion density wave in a Rashba Hund's insulator model, using unbiased simulations, with potential realization in multiorbital thin films.

Contribution

It introduces a new magnetic phase hosting antiferromagnetic skyrmions and a skyrmion density wave in a realistic microscopic model, supported by unbiased simulations.

Findings

Discovery of antiferromagnetic skyrmions in the model

Identification of a skyrmion density wave with ($Q,Q$) modulation

Prediction of experimental realization in multiorbital thin films

Abstract

We discover magnetic phases hosting highly-elusive and technologically important antiferromagnetic skyrmion quasiparicles in a model for Rashba-coupled Hund's insulator. The results are based on unbiased simulations of a classical superexchange model derived, in this work, from a realistic microscopic electronic Hamiltonian. We also discover a novel skyrmion density wave groundstate 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.