d0 Magnetic Skyrmions in Two-Dimensional Lattice

Magnetic skyrmions are topologically protected chiral spin textures that hold great promise for information storage and processing. The current research efforts on magnetic skyrmions are exclusively based on d-orbital magnetism, which restricts their existence in a narrow window of temperature-external magnetic field (T-B) phase diagram. Herein, employing first-principles and Monte-Carlo simulations, the work reports the identification of d⁰ magnetic skyrmions in 2D lattice of Tl₂NO₂. Arising from inversion asymmetry and strong spin-orbit coupling compensated by ligand of heavy element, large Dzyaloshinskii–Moriya interaction is obtained in monolayer Tl₂NO₂. This, competed with p-orbital exchange interaction, leads to the d⁰ skyrmion physics under external magnetic field. Importantly, different from d-orbital topological magnetism, the d⁰ magnetic skyrmions can be stabilized in a wide window of T-B phase diagram. The underlying physics is related to the small magnetic moment and delocalization character of d⁰ magnetism. Furthermore, the work also demonstrates that the d⁰ magnetic skyrmions are strongly coupled with ferroelectricity. These findings open a new direction for magnetic skyrmion research.