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Formation mechanism of helical Q structure in Gd-based skyrmion materials

ORAL

Abstract

Recently, short-period skyrmion phases have been observed in Gd-based compounds[1-3]. Using the ab initio local force method, we investigate the formation mechanism of the helical spin structure in GdRu2Si2 and Gd2PdSi3[4]. We calculate the paramagnetic spin susceptibility and find that the Fermi surface nesting is not the origin of the incommensurate modulation, in contrast to the naive scenario based on the Ruderman-Kittel-Kasuya-Yosida mechanism. We then decompose the exchange interactions between the Gd spins into each orbital component, and show that spin-density-wave type interaction between the Gd-5d orbitals is ferromagnetic, but the interaction between the Gd-4f orbitals is antiferromagnetic. We conclude that the competition between these two interactions, namely, the inter-orbital frustration, stabilizes the finite-Q structure.
[1] T. Kurumaji et al., Science 365, 914 (2019).
[2] M. Hirschberger et al., Nat. Commun. 10, 5831 (2019).
[3] N. D. Khanh et al., Nat. Nanotechnol. 15, 444 (2020)
[4] T. Nomoto, T. Koretsune, and R. Arita, Phys. Rev. Lett. 125, 117204 (2020).

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Presenters

  • Takuya Nomoto

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

Authors

  • Takuya Nomoto

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

  • Takashi Koretsune

    Tohoku Univ., Tohoku University, Department of Physics, Tohoku University, Tohoku Univ

  • Ryotaro Arita

    Univ of Tokyo, University of Tokyo, Department of Applied Physics, Univ of Tokyo, CEMS, RIKEN, Department of Applied Physics, The University of Tokyo, RIKEN-CEMS