Noninvasive probing of local inversion symmetry breaking and its correlation in van der waals ferromagnet

ORAL

Abstract

The stabilization of topologically protected magnetic skyrmions is a key focus in condensed matter physics. Their robustness against deformation makes them promising for next-generation, energy-efficient data storage. Van der Waals magnets offer an ideal platform, and Fe₃GaTe₂ (FGaT) stands out for its high Curie temperature (above room temperature) and diverse skyrmionic states [1–5]. These textures arise from competing interactions: the Dzyaloshinskii–Moriya interaction (DMI) from local inversion-symmetry breaking favors Néel-type skyrmions, while dipolar–DMI interplay stabilizes Bloch or hybrid states. Remarkably, skyrmions can form even in centrosymmetric crystals when such mechanisms coexist. Although FGaT's average structure (P6₃/mmc) is centrosymmetric, HAADF-STEM reveals Fe-ion off-center displacements (~10 pm) over several unit cells [2]. In slightly Fe-deficient samples (<10 %), these displacements break local inversion symmetry while preserving the global one—providing a microscopic route to DMI and Néel-type skyrmions. To probe this short-range disorder, we employ high-energy X-ray diffuse scattering and 3D-ΔPDF [6,7] analysis on FGaT with varying Fe content to quantify picometer-scale Fe displacements, their 3D correlations, and the evolution of local inversion-symmetry breaking that stabilizes skyrmions.

*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

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Presenters

  • Joohee Bang

    • Argonne National Laboratory

Authors

  • Joohee Bang

    • Argonne National Laboratory

  • Hyo-Bin Ahn

    • Argonne National Laboratory

  • Stephan Rosenkranz

    • Argonne National Laboratory