The Double-$Q$ Ground State with Topological Charge Stripes in the Skyrmion Candidate ${\text{GdRu}}_{\text{2}}{\text{Si}}_{\text{2}}$

Abstract

${\text{GdRu}}_{\text{2}}{\text{Si}}_{\text{2}}$ is a centrosymmetric magnet in which a skyrmion lattice has recently been discovered. Here, we investigate the magnetic structure of the zero field ground state using neutron diffraction on single crystal and polycrystalline ${}^{\text{160}}{\text{GdRu}}_{\text{2}}{\text{Si}}_{\text{2}}$. In addition to observing the principal propagation vectors ${\mathbf{q}}_1$ and ${\mathbf{q}}_2$, we discover higher order magnetic satellites, notably ${\mathbf{q}}_1+2{\mathbf{q}}_2$. The appearance of these satellites are explained within the framework of a new double-$Q$ constant-moment solution. Using powder diffraction we implement a quantitative refinement of this model. This structure, which contains vortexlike motifs, is shown to have a one-dimensional topological charge density.

Accepted PRB Letter (14.4.2023)