SKM 2021 – scientific programme

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MA: Fachverband Magnetismus

MA 10: Focus Session: Higher-Order Magnetic Interactions - Implications in 2D and 3D Magnetism I

MA 10.1: Invited Talk

Wednesday, September 29, 2021, 13:30–14:00, H5

Topological spin crystals stabilized by itinerant frustration — •Yukitoshi Motome — The University of Tokyo, Tokyo, Japan

Topological spin crystals, which are periodic arrays of topological spin textures such as vortices, skyrmions, and hedgehogs, have attracted numerous attention for the potential use of their magnetic, transport, and optical properties for future spintronics and quantum computing. For materializing such unconventional magnetism, it is crucially important to understand the relevant magnetic interactions. Widely known is the Dzyaloshinskii-Moriya interaction, which stabilizes swirling spin textures in competition with ferromagnetic exchange interactions. Here, we theoretically study a different mechanism driven by effective magnetic interactions arising from itinerant nature of electrons. We show that, in addition to the well-known Ruderman-Kittel-Kasuya-Yosida interaction, multiple-spin interactions naturally arise as higher-order contributions from the spin-charge coupling in itinerant magnets. They are intrinsically long-ranged and have characteristic wave numbers specified by the Fermi surfaces, like the Ruderman-Kittel-Kasuya-Yosida interaction. We find that frustration among such long-range multiple-spin interactions, which we call itinerant frustration, can stabilize a variety of topological spin crystals with unique features, even in centrosymmetric systems where the Dzyaloshinskii-Moriya interaction is absent. We discuss our results with recent advances in experiments.