Large Magneto-thermopower in MnGe with topological spin texture

ORAL

Abstract

A topological spin texture—a three-dimensional array of hedgehogs and anti-hedgehogs—shows up in a chiral magnet MnGe. Those hedgehog-type spin textures serve as “emergent” magnetic monopoles whose fluctuations critically affect charge transport phenomena.
We report an unusual magneto-thermopower which exhibits a strong enhancement towards the topological phase transition (hedgehog lattice to ferromagnetic state) with applying magnetic field. By considering all conceivable origins through quantitative investigations on electronic structures and properties, a possible origin of the observed effect is assigned to unconventional scattering mechanism arising from the dynamics of emergent magnetic field. The proposed mechanism is also corroborated by high field measurements of Seebeck effect and magneto-resistivity, which revealed the far-reaching effect of surviving magnetic fluctuations even in the ferromagnetic region.
Our finding will not only illustrate the unique topological phenomena rooted in the dense lattice of singular defects like hedgehogs, but may also motivate the search of thermoelectric functions in topological magnets.

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Presenters

  • Yukako Fujishiro

    • Applied Physics, Univ of Tokyo

Authors

  • Yukako Fujishiro

    • Applied Physics, Univ of Tokyo

  • Naoya Kanazawa

    • Applied Physics, Univ of Tokyo
    • Department of Applied Physics, University of Tokyo

  • Takahiro Shimojima

    • CEMS, RIKEN

  • Asuka Nakamura

    • Applied Physics, Univ of Tokyo

  • Kyoko Ishizaka

    • Applied Physics, Univ of Tokyo
    • The University of Tokyo

  • Takashi Koretsune

    • CEMS, RIKEN

  • Ryotaro Arita

    • RIKEN
    • RIKEN Center for Emergent Matter Science
    • CEMS, RIKEN
    • Center for Emergent Matter Science, RIKEN

  • Atsushi Miyake

    • The Institute for Solid State Physics, The University of Tokyo
    • University of Tokyo
    • ISSP, The University of Tokyo
    • Institute of Solid State Physics (ISSP), Univ of Tokyo

  • Hiroyuki Mitamura

    • ISSP, The University of Tokyo

  • Kazuto Akiba

    • The Institute for Solid State Physics, The University of Tokyo
    • ISSP, The University of Tokyo
    • Institute of Solid State Physics (ISSP), Univ of Tokyo

  • Masashi Tokunaga

    • The Institute for Solid State Physics, The University of Tokyo
    • University of Tokyo
    • ISSP, The University of Tokyo
    • Institute of Solid State Physics (ISSP), Univ of Tokyo

  • Shojiro Kimura

    • IMR, Tohoku University

  • Satoshi Awaji

    • IMR, Tohoku University

  • Shiogai Junichi

    • Institute for Materials Reaserch, Tohoku University
    • Tohoku Univ
    • IMR, Tohoku University
    • Institute for Materials Research

  • Atsushi Tsukazaki

    • Institute for Materials Reaserch, Tohoku University
    • Tohoku Univ
    • Institute for Materials Research, Tohoku University
    • IMR, Tohoku University
    • Institute for Materials Research
    • Tohoku University
    • Tohoku Univ.

  • Akiko Kikkawa

    • RIKEN Center for Emergent Matter Science (CEMS)
    • CEMS, RIKEN

  • Yasujiro Taguchi

    • RIKEN Center for Emergent Matter Science (CEMS)
    • CEMS, RIKEN

  • Yoshinori Tokura

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