Structural investigation of the insulator-metal transition in NiS2−xSex compounds

ORAL

Abstract

We report [1] on a combined measurement of high-resolution x-ray diffraction on powder and Raman scattering on single crystalline NiS2-xSex samples that exhibit the insulator-metal (IM) transition [2] with Se doping. Via x-rays, an abrupt change in the bond length between Ni and S (Se) ions was observed at the transition temperature, in sharp contrast to the almost constant bond length between chalcogen ions. Raman scattering, a complementary technique with the unique sensitivity to the vibrations of chalcogen bonds, revealed no anomalies in the phonon spectrum, consistent with the x-ray diffraction results. This indicates the important role of the interaction between Ni and S (Se) in the IM transition. The potential implication of this interpretation is discussed in terms of current theoretical models.

[1] Garam Han, Sungkyun Choi, Hwanbeom Cho, Byungmin Sohn, Je-Geun Park, and Changyoung Kim, Physical Review B 98, 125114 (2018).
[2] For a review, see M. Imada, A. Fujimori, and Y. Tokura, Rev. Mod. Phys. 70, 1039 (1998) and references therein.

*The work at the IBS-CCES was funded by Institute of Basic Science in Korea (Grants No. IBS-R009-G1, G2). S. C. was also supported by the international postdoctoral scholarship at Max Planck Institute for Solid State Research in Germany.

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Presenters

  • Sungkyun Choi

    • Department of Physics and Astronomy, Rutgers University

Authors

  • Sungkyun Choi

    • Department of Physics and Astronomy, Rutgers University

  • Garam Han

    • Department of Physics and Astronomy, Seoul National University (SNU)

  • Hwanbeom Cho

    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Department of Physics and Astronomy, Seoul National University

  • Byungmin Sohn

    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Seoul National University

  • Je-Guen Park

    • Department of Physics and Astronomy, Seoul National University
    • Center for Correlated Electron Systems, Institute for Basic Science & Seoul National Univeristy
    • 2 Center for Correlated Electron Systems, institute for Basic Science; and 3 Department of Physics and Astronomy ,Seoul National University, Seoul, South Korea
    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Seoul National University
    • Department of Physics & Astronomy, Seoul National University, Seoul, Korea
    • Center for Correlated Electron Systems, Institute for Basic Science (IBS), Korea

  • Changyoung Kim

    • Department of Physics and Astronomy, Seoul National University (SNU)
    • Physics and astronomy, Seoul National University
    • Seoul National University
    • CCES-IBS
    • Institute for Basic Science
    • IBS-CCES, Seoul National University