Centers & Labs

RIKEN Center for Emergent Matter Science

Strong Correlation Quantum Structure Research Team

Team Leader: Takahisa Arima (Ph.D.)
Takahisa  Arima(Ph.D.)

Strongly correlated electron systems may exhibit various interesting emergent phenomena such as superconductivity, colossal magneto-resistance, and giant magneto-electric effects.  These emergent phenomena are directly associated with the spatial distributions as well as the spatial and temporal fluctuations of atoms, electron density, and spin density.  We are going to perform crystallographic and magnetic structure analyses, spectroscopies, and microscopies by using synchrotron x-rays, neutrons, and high-energy electron beams to reveal them.

Main Research Field

Materials Sciences

Related Research Fields


Research Subjects

  • X-ray-, neutron-, and electron-diffraction studies of superstructure in lattice, charge, orbital, and spin degrees of freedom in strongly-correlated electron systems
  • X-ray and neutron spectroscopies of temporal and spatial fluctuations in lattice, charge, orbital, and spin degrees of freedom in strongly-correlated electron systems
  • Real-space imaging of heterogeneous structures in strongly correlated electron systems by using x-ray and electron beams

Selected Publications

  1. Nakajima T., Takahashi Y., Kibayashi S., Matsuda M., Kakurai K., Ishiwata S., Taguchi Y., Tokura Y., Arima T.:
    “Electromagnon excitation in the field-induced noncollinear ferrimagnetic phase of Ba2Mg2Fe12O22 studied by polarized inelastic neutron scattering and terahertz time-domain optical spectroscopy”
    Phys. Rev. B 93, 035119 (2016).
  2. Yamasaki Y., Morikawa D., Honda T., Nakao H., Murakami Y., Kanazawa N., Kawasaki M., Arima T., Tokura Y.:
    “Dynamical process of skyrmion-helical magnetic transformation of the chiral-lattice magnet FeGe probed by small-angle resonant soft x-ray scattering”
    Phys. Rev. B 92, 220421(R) (2015).
  3. Morikawa D., Yu X. Z., Kaneko Y., Tokunaga Y., Nagai T., Kimoto K., Arima T., Tokura Y.:
    “Lorentz transmission electron microscopy on nanometric magnetic bubbles and skyrmions in bilayered manganites La1.2Sr1.8(Mn1−yRuy)2O7 with controlled magnetic anisotropy”
    Appl. Phys. Lett. 107, 212401 (2015).
  4. Nakajima T., Tokunaga Y., Taguchi Y., Tokura Y., Arima T.:
    “Piezomagnetoelectric Effect of Spin Origin in Dysprosium Orthoferrite”
    Phys. Rev. Lett. 115, 197205(2015).
  5. Nii Y., Nakajima T., Kikkawa A., Yamasaki Y., Ohishi K., Suzuki J., Taguchi Y., Arima T., Tokura Y., Iwasa Y.:
    “Uniaxial stress control of skyrmion phase”
    Nature Commun. 6, 8539 (2015).
  6. Tardif S., Takeshita S., Ohsumi H., Yamaura J., Okuyama D., Hiroi Z., Takata M., Arima T.:
    “All-In-All-Out Magnetic Domains: X-Ray Diffraction Imaging and Magnetic Field Control”
    Phys. Rev. Lett. 114, 147205 (2015).
  7. Nakajima T., Tokunaga Y., Kocsis V., Taguchi Y., Tokura Y., Arima T.:
    “Uniaxial-Stress Control of Spin-Driven Ferroelectricity in Multiferroic Ba2CoGe2O7
    Phys. Rev. Lett. 114, 067201 (2015).
  8. Okuyama D., Shibuya K., Kumai R., Suzuki T., Yamasaki Y., Nakao H., Murakami Y., Kawasaki M., Taguchi Y., Tokura Y., Arima T.:
    “X-ray study of metal-insulator transitions induced by W-doping and photoirradiation in VO2 films”
    Phys. Rev. B 91, 064101 (2015).
  9. Okuyama D., Nakano M., Takeshita S., Ohsumi H., Tardif S., Shibuya K., Hatano T., Yumoto H., Koyama T., Ohashi H., Takata M., Kawasaki M., Arima T., Tokura Y., Iwasa Y.:
    “Gate-tunable gigantic lattice deformation in VO2
    Appl. Phys. Lett. 104, 023507 (2014).
  10. Fujiyama S., Ohsumi H., Ohashi K., Hirai D., Kim B. J., Arima T., Takata M., Takagi H.:
    “Spin and Orbital Contributions to Magnetically Ordered Moments in 5d Layered Perovskite Sr2IrO4
    Phys. Rev. Lett. 112, 016405 (2014).

Lab Members

Principal Investigator

Takahisa Arima
Team Leader

Core Members

Taro Nakajima
Research Scientist
Daisuke Morikawa
Postdoctoral Researcher
Victor Ukleev
Postdoctoral Researcher
Kiyou Shibata
Special Postdoctoral Researcher

Contact information

2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Email: takahisa.arima [at]

Related links

Recent research results

June 10, 2017: RIKEN RESEARCH
A skyrmion square dance
October 13, 2015: Press Release
Just a touch of skyrmions