Emergent Phenomena Observation Technology Research Team

Principal Investigator

PI Name Seigo Tarucha
Degree D.Eng.
Title Team Leader
Brief Resume
1978 Staff Member at the Basic Research Laboratories of Nippon Tel. & Tel. Corp.
1985 Senior Researcher at the Basic Research Laboratories of Nippon Tel. & Tel. Corp.
1986 Visiting Scientist, Max-Planck-Institute FKF (Stuttgart, Germany)(-1987)
1989 Principal Researcher at the Basic Research Laboratories of Nippon Tel. & Tel. Corp.
1990 Group Leader, Research Group on Electron Transport in Low-Dimensional Semiconductor Structures, NTT Basic Research Laboratories(-1998)
1994 Distinguished Scientist, NTT Basic Research Laboratories (-1998)
1995 Visiting Professor, Technical University of Delft (The Netherlands)
1998 Professor, Department of Physics, University of Tokyo (-2004)
2004 Professor, Department of Applied Physics, University of Tokyo (-2018)
2012 Visiting Professor, Institut Néel CNRS, université Joseph Fourier (France)
2013 Division Director, Quantum Information Electronics Division, RIKEN Center for Emergent Matter Science (-present)
2013 Group Director, Quantum Functional System Research Group, RIKEN Center for Emergent Matter Science (-present)
2018 Deputy Director, RIKEN Center for Emergent Matter Science
2019 Guest Professor, Department of Physics, Tokyo University of Science (-present)
2020 Team Leader, Semiconductor Quantum Information Device Research Team, RIKEN Center for Quantum Computing (-present)
2024 Team Leader, Emergent Phenomena Observation Technology Research Team, RIKEN Center for Emergent Matter Science (-present)

Outline

For observing and analyzing emergent matter phenomena, we use advanced electron microscopy, especially electron holography. Electron holography is a leading-edge observation technology that utilizes interference effects of electron waves and visualizes electromagnetic fields on the nanometer scale. By developing multifunctional transmission electron microscope-specimen holders equipped with plural probes, changes in the electromagnetic fields in and around specimens under applied voltages and magnetic fields are quantitatively investigated. By improving resolutions and precisions of these observation technologies, we can extensively study mechanisms of emergent matter phenomena in newly designed specimens for investigating many-body systems with multiple degrees of freedom.

Research Fields

Materials Science, Physics, Engineering

Keywords

Imaging
Electron microscopy
Lorentz microscopy
Flux quantum
Electron holography
Nanomagnetism

Results

In situ observation of accumulation and collective motion of electrons

Comprehensive understanding of electromagnetic fields requires their visualization both inside and outside of materials. Since electromagnetic fields originate from various motions of electrons, comprehensive study of motions of electrons is of vital importance as well as of significant interest for understanding various emergent phenomena. The purpose of this study is to extend electron holography technology to visualize motions of electrons. By detecting electric field variations through amplitude reconstruction processes for holograms, we have succeeded in visualizing collective motions of electrons around various insulating materials. The lower right figures below show one of our experimental results of visualization of the collective motions of electrons around microfibrils of sciatic nerve tissue. In these reconstructed amplitude images, the bright yellow regions indicate the area where electric field fluctuates due to the motions of electrons. At the initial state (top figure),the electric field variations are not prominent. When the electron irradiation continues, however, bright yellow regions appear and the position of the regions changes gradually between the two branches as indicated by black arrows in the lower figures. These results indicate that the collective motions of electrons can be detected through electric field variation and can be visualized through amplitude reconstruction process for holograms.

Reconstructed amplitude images around microfibrils of sciatic nerve tissue (green).The bright yellow regions indicate the area where electric field fluctuates due to motions of electrons.

Members

Seigo Tarucha

 Team Leader tarucha[at]riken.jp

Ken Harada

 Senior Research Scientist

Yoh Iwasaki

 Technical Scientist

Keiko Shimada

 Technical Staff I

Publications

  1. K. Niitsu, Y. Liu, A. Booth, X. Yu, N. Mathur, M. Stolt, D. Shindo, S. Jin, J. Zang, N. Nagaosa, and Y. Tokura

    Geometrically stabilized skyrmionic vortex in FeGe tetrahedral nanoparticles

    Nat. Mater. 21, 305–310 (2022)
  2. H. Idzuchi, F. Pientka, K. F. Huang, K. Harada, O. Gul, Y. J. Shin, L. T. Nguyen, N. H. Jo, D. Shindo, R. J. Cava, P. C. Canfield, and P. Kim

    Unconventional supercurrent phase in Ising superconductor Josephson junction with atomically thin magnetic insulator

    Nat. Commun. 12, 5332 (2021)
  3. D. Shindo, and Z. Akase

    Direct observation of electric and magnetic fields of functional materials

    Mater. Sci. Eng. R Rep. 142, 100564 (2020)
  4. D. Shindo, T. Tanigaki, and H. S. Park

    Advanced Electron Holography Applied to Electromagnetic Field Study in Materials Science

    Adv. Mater. 29, 1602216 (2017)
  5. M. Nakamura, F. Kagawa, T. Tanigaki, H. S. Park, T. Matsuda, D. Shindo, Y. Tokura, and M. Kawasaki

    Spontaneous Polarization and Bulk Photovoltaic Effect Driven by Polar Discontinuity in LaFeO3/SrTiO3 Heterojunctions

    Phys. Rev. Lett. 116, 156801 (2016)

Articles

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