Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/02

  • 研究者氏名
    Researcher Name

    那波和宏 Kazuhiro NAWA
    准教授 Associate Professor
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    Division of Inorganic Material Research
  • 研究キーワード
    Research Keywords

    Magnetic quasiparticles
    Topological properties
    Neutron scattering
Research Subject
Exploring magnetic excitations with topological nature using neutron scattering technique

研究の背景 Background


Magnetic quasiparticles, such as magnons and triplons, can propagate in magnetic materials like Bloch waves of electrons in a solid. Recently, a concept of topology, which represents the connectivity of wavefunctions, has been not only discussed for electrons but also extended to magnetic quasiparticles. In an electron system, the difference in the topology inside and outside of a solid leads to the nondissipative electron flows on the bulk surface. On the other hand, it has been unknown whether magnetic quasipalticles can realize nondissipasive surface states like electrons.

研究の目標 Outcome


The purpose of this study is to detect nontrivial topology of magnetic quasiparticles by using neutron scattering, and explore new physical properties induced by magnetic quasiparticles. Utilizing the nondissipative surface states of magnetic quasiparticles may lead to the further development of energy efficient information transmission and processing materials.

研究図Research Figure

Fig.1. (a) Interdimer network in Ba2CuSi2O6Cl2 equivalent to (b) SSH chains weakly coupled by interchain hopping terms. Solid black circles represent triplons localized at the edge of the chains. Solid red, dashed yellow, and thin blue lines indicate magnetic interactions with different magnitudes.

Fig.2. (a) Energy-momentum maps of the scattering intensities along the (H, 0) or (0, K) direction compared with (b) dispersion relations of the weakly coupled SSH model. Intensity is integrated for the K or H range of ±0.10 and the entire observed L range.

文献 / Publications

K. Nawa et al., Nat. Comnun. 10, 2096 (2019).; K. Nawa et al., Phys. Rev. Research 2, 043121 (2020).