Interface-Induced Stability of Nontrivial Topological Spin Textures: Unveiling Room-Temperature Hopfions and Skyrmions

POSTER

Abstract

Topological spin textures such as skyrmions and hopfions provide a platform for dissipationless information transport and nonvolatile magnetic logic, yet their realization at ambient conditions remains limited by thermal instability and field-dependent initialization. We demonstrate the first observation of room-temperature hopfion–skyrmion assemblies stabilized without external magnetic fields in ferromagnet/topological insulator/ferromagnet (EuS/Bi2Se3/EuS) trilayers. Lorentz transmission electron microscopy directly reveals triangular skyrmion lattices encircled by hopfion rings, confirming the coexistence of 2D and 3D chiral topologies. Polarized neutron reflectometry and XMCD uncover persistent interfacial ferromagnetism up to 300 K, driven by interfacial Dzyaloshinskii–Moriya interactions and magnetic proximity coupling extending several nanometers into the topological insulator. Micromagnetic modeling quantitatively reproduces the emergent textures and maps the stability regime set by DMI strength, uniaxial anisotropy, and geometric confinement. These results reveal an interface-driven route to stabilize zero-field topological solitons at room temperature, opening opportunities for ultralow-power spintronics, reconfigurable logic, and topological quantum devices.

*This work was supported by the Army Research Office under Grant No. W911NF-20-2-0061, the National Science Foundation under Grant Nos. DMR-2218550 and DMR-1207469, and the Office of Naval Research under Grants N00014-20-1-2306 and N00014-13-1-0301, NSF-DMR-1231319, the ERC Starting Grant SKYNOLIMIT 948063, ERC Proof of Concept project SuperPHOTON 101100718. Research conducted at Oak Ridge National Laboratory (ORNL) was supported by the U.S. Dept. of Energy (DOE), Office of Science, Office of Basic Energy Sciences, and utilized resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by ORNL. D.H. acknowledges support from the NSF-DMR-1905662 and the AFOSR FA9550-20-1-0247. Use of the Advanced Photon Source was supported by the U.S. DOE, Office of Science, Office of Basic Energy Sciences, (No. DE-AC02-06CH11357).

Publication: F. Katmis, V. Lauter, R. Yagan, et al. " Interface-Induced Stability of Nontrivial Topological Spin Textures: Unveiling Room-Temperature Hopfions and Skyrmions." Adv. Mater. (2025): e11754. https://doi.org/10.1002/adma.202511754

Presenters

  • Mehmet Cengiz Onbasli

    • Koc University

Authors

  • Mehmet Cengiz Onbasli

    • Koc University

  • Ferhat Katmis

    • MIT, Koc University
    • Koc University, MIT

  • Valeria Lauter

    • Oak Ridge National Laboratory

  • Rawana Yagan

    • Koc University

  • Iuri S Brandt

    • Universida de Federal de Viçosa

  • Arash Mousavi Cheghabouri

    • Koc University

  • Hua Zhou

    • Argonne National Laboratory

  • John William Freeland

    • Argonne National Laboratory

  • Clodoaldo de Araujo

    • Universida de Federal de Viçosa

  • Michelle E Jamer

    • US Naval Academy

  • Don Heiman

    • Northeastern University

  • Jagadeesh S Moodera

    • Massachusetts Institute of Technology