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Strongly pinned skyrmionic bubbles and higher-order nonlinear Hall effect at the interface of Pt/FeSi bilayer

ORAL

Abstract

A nonmagnetic insulator FeSi has been shown to host a two-dimensional ferromagnetic metal state at the surface [1]. Unlike the topological insulators, the electronic state of FeSi is characterized by a quantum geometric phase, so-called Zak phase. As a consequence of the nearly quantized Zak phase of bulk electronic state, a giant surface polarization emerges, forming the surface band with strong spin-orbit coupling (SOC) and thus hosting good electrical conduction and high ferromagnetic ordering. In addition, electrical conduction and magnetic properties could be dramatically modulated by the chemical species of capping insulator material owing to the moderate chemical activity of the FeSi surface state [2].

In this study, we investigated SOC proximity effect of Pt capping on FeSi for enhancing the interfacial Dzyaloshinskii-Moriya interaction. We could realize the emergence of strongly pinned skyrmionic bubbles (SkBs) and their current-driven transformation. This strong pinning effects prevent the collapse of SkBs in the high current density regime, leading to the development of higher-order nonlinear Hall effects of the spin-chirality origin [3].



[1] Y. Ohtsuka, N. Kanazawa, M. Hirayama et al., Sci. Adv. 7, eabj0498 (2021).

[2] T. Hori, N. Kanazawa, M. Hirayama et al., Adv. Mater. 35, 2206801 (2023).

[3] T. Hori, N. Kanazawa et al., Phys. Rev. Mater. 8, 044407 (2024).

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Publication: T. Hori, N. Kanazawa, K. Matsuura, H. Ishizuka, K. Fujiwara, A. Tsukazaki, M. Ichikawa , M. Kawasaki, F. Kagawa, M. Hirayama and Y. Tokura, Physical Review Materials 8, 044407 (2024).

Presenters

  • Tomohiro Hori

    Department of Applied Physics and Institute of Industrial Science, University of Tokyo

Authors

  • Tomohiro Hori

    Department of Applied Physics and Institute of Industrial Science, University of Tokyo

  • Naoya Kanazawa

    Institute of Industrial Science, University of Tokyo

  • Keisuke Matsuura

    Department of Physics, Institute of Science Tokyo, RIKEN Center for Emergent Matter Science (CEMS)

  • Hiro Ishizuka

    Institute of Science Tokyo (formerly Tokyo Tech), Department of Physics, Institute of Science Tokyo

  • Kohei Fujiwara

    Department of Chemistry, Rikkyo University

  • Atsushi Tsukazaki

    Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo

  • Masakazu Ichikawa

    Department of Applied Physics, University of Tokyo

  • Masashi Kawasaki

    RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo

  • Fumitaka Kagawa

    Department of Physics, Institute of Science Tokyo, RIKEN Center for Emergent Matter Science (CEMS)

  • Motoaki Hirayama

    RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo

  • Yoshinori Tokura

    RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Univ of Tokyo, The University of Tokyo, RIKEN Center for Emergent Matter Science (CEMS), Tokyo college, The University of Tokyo, RIKEN Center for Emergent Matter Science (CEMS); Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), Univ. of Tokyo; Tokyo College, Univ. of Tokyo, RIKEN Center for Emergent Matter Science (CEMS), Department of Applied Physics, Quantum-Phase Electronics Center (QPEC) and Tokyo College, University of Tokyo