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RIKEN Center for Emergent Matter Science Electronic States Spectroscopy Research Team

Team Leader: Kyoko Ishizaka (Ph.D.)

Research Summary

Kyoko  Ishizaka(Ph.D.)

We investigate spin, electron, and crystal structures of materials showing a variety of physical properties, functions, and quantum phenomena. We use spin- and angle-resolved photoemission spectroscopy, which can probe the energy, momentum, and spin of electrons in solids, to study new materials and phenomena such as superconductors, thermoelectric / spintronic materials, topological quantum states, and many-body effects in strongly correlated systems. We are also starting a project on the ultrafast time-resolved transmission electron microscope utilizing pulsed lasers. Dynamics of spin, electron, and crystal structures in nanometer and femto-nanosecond scales will be explored.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Interdisciplinary Science & Engineering


  • Photoemission Spectroscopy
  • Ultrafast TEM
  • Nano-scale magnetism
  • Superconductivity
  • Strongly correlated system

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.

  • 1.T. Shimojima, Y. Suzuki, A. Nakamura, N. Mitsuishi, S. Kasahara, T. Shibauchi, Y. Matsuda, Y. Ishida, S. Shin, and K. Ishizaka.:
    "Ultrafast nematic-orbital excitation in FeSe"
    Nat. Commun. 10, 1946 (2019).
  • 2.A. Nakamura, T. Shimojima, M. Matsuura, Y. Chiashi, M. Kamitani, H. Sakai, S. Ishiwata, H. Li, A. Oshiyama and K. Ishizaka.:
    "Evaluation of photo-induced shear strain in monoclinic VTe2 by ultrafast electron diffraction"
    Appl. Phys. Express 11, 092601 (2018).
  • 3.Shin-ichiro Ideta, Dongfang Zhang, Arend G. Dijkstra, Sergey Artyukhin, Sercan Keskin, Roberto Cingolani, Takahiro Shimojima, Kyoko Ishizaka, Hiroyuki Ishii, Kazutaka Kudo, Minoru Nohara and R. J. Dwayne Miller.:
    "Ultrafast dissolution and creation of bonds in IrTe2 induced by photodoping"
    Sci. Adv. 4, eaar3867 (2018).
  • 4.T. Sonobe, T. Shimojima, A. Nakamura, M. Nakajima, S.Uchida, K. Kihou, C.H. Lee, A. Iyo, H. Eisaki, K. Ohgushi, and K. Ishizaka.:
    "Orbital-anisotropic electronic structure in the nonmagnetic state of BaFe2(As1-xPx)2 superconductors"
    Sci. Rep. 8, 2169 (2018).
  • 5.T. Shimojima, W. Malaeb, A. Nakamura, T. Kondo, K. Kihou, C. H. Lee, A. Iyo, H. Eisaki, S. Ishida, M. Nakajima, S. Uchida, K. Ohgushi, K. Ishizaka, and S. Shin.:
    "Antiferroic electronic structure in the nonmagnetic superconducting state of the iron-based superconductors"
    Sci. Adv. 3, e1700466 (2017).
  • 6.M. Sakano,M. S. Bahramy, H. Tsuji, Araya, K. Ikeura, H. Sakai, S. Ishiwata, K. Yaji, K. Kuroda, A. Harasawa, S. Shin, and K. Ishizaka.:
    "Observation of spin-polarized bands and domain-dependent Fermi arcs in polar Weyl semimetal MoTe2"
    Phys. Rev. B 95, 121101(R) (2017).
  • 7.A. Nakamura, T. Shimojima, T. Sonobe, S. Yoshida, K. Ishizaka, W. Malaeb, S. Shin, S. Iimura, S. Matsuishi, and H. Hosono.:
    "Multiple-pseudogap phases in the hydrogen-doped LaFeAsO system"
    Phys. Rev. B 95, 064501 (2017).
  • 8.A. Nakamura, T. Shimojima, M. Nakano, Y. Iwasa, and K. Ishizaka.:
    "Electron and lattice dynamics of transition metal thin films observed by ultrafast electron diffraction and transient optical measurements"
    Struct, Dyn. 3, 064501 (2016).
  • 9.Y. Suzuki, T. Shimojima, T. Sonobe, A. Nakamura, M. Sakano, H. Tsuji, J. Omachi, K. Yoshioka, M. Kuwata-Gonokami, T. Watashige, R. Kobayashi, S. Kasahara, T. Shibauchi, Y. Matsuda, Y. Yamakawa, H. Kontani, and K. Ishizaka.:
    "Momentum-dependent sign inversion of orbital order in superconducting FeSe"
    Phys. Rev. B, 92, 205117 (2015).
  • 10.M. Sakano, K. Okawa, M. Kanou, H. Sanjo, T. Okuda, T. Sasagawa, and K. Ishizaka.:
    Topologically protected surface states in a centrosymmetric superconductor β-PdBi2"
    Nat. Commun., 6, 8595 (2015).

Recent Research Results

Related Links

Lab Members

Principal investigator

Kyoko Ishizaka
Team Leader

Core members

Takahiro Shimojima
Senior Scientist
Asuka Nakamura
Postdoctoral Researcher
Natsuki Mitsuishi
Postdoctoral Researcher

Contact Information

304-1, Frontier Research Laboratory
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Tel: +81-(0)48-467-4492
Fax: +81-(0)48-462-1687
Email: kyoko.ishizaka [at] riken.jp