Centers & Labs

RIKEN Center for Emergent Matter Science

Emergent Phenomena Measurement Research Team

Team Leader: Tetsuo Hanaguri (D.Eng.)
Tetsuo  Hanaguri(D.Eng.)

We experimentally study electronic states behind emergent phenomena in electron systems, such as high-temperature superconductivity and topological quantum phenomena. For this purpose, we use scanning tunneling microscopes working under combined extreme conditions of very low temperature, high magnetic field and ultra-high vacuum. Modern scanning-tunneling-microscopy technology enables us to obtain a “map of the electronic state” with atomic-scale spatial resolution and energy resolution as high as micro electron volt. We will make and analyze the maps of various materials and try to establish the relationships between material properties and electronic states. We also aim to improve and functionalize the scanning tunneling microscope and pursue the development of novel measurement techniques to discover new emergent phenomena in condensed matter.

Main Research Field

Mathematical and physical sciences

Related Research Fields

Interdisciplinary science and engineering

Keywords

  • Superconductivity
  • Topological quantum phenomena
  • Scanning probe microscopy

Selected Publications

  1. Kohsaka, Y., Machida, T., Iwaya, K., Kanou, M., Hanaguri, T., and Sasagawa, T.:
    "Spin-orbit scattering visualized in quasiparticle interference"
    Phys. Rev. B 95, 115307 (2017)
  2. Machida, T., Kohsaka, Y., Matsuoka, K., Iwaya, K., Hanaguri, T., and Tamegai, T.:
    "Bipartite electronic superstructures in the vortex core of Bi2Sr2CaCu2O8+δ"
    Nature Commun. 7, 11747 (2016)
  3. Fu, Y.-S., Hanaguri, T., Igarashi, K., Kawamura, M., Bahramy, M. S., and Sasagawa,T.:
    "Observation of Zeeman effect in topological surface state with distinct material dependence"
    Nature Commun. 7, 10829 (2016)
  4. Watashige, T., Tsutsumi, Y., Hanaguri, T., Kohsaka, Y., Kasahara, S., Furusaki, A., Sigrist, M., Meingast, C., Wolf, T., Löhneysen, H. v., Shibauchi, T., and Matsuda, Y.:
    "Evidence for Time-Reversal Symmetry Breaking of the Superconducting State near Twin-Boundary Interfaces in FeSe Revealed by Scanning Tunneling Spectroscopy"
    Phys. Rev. X 5, 031022 (2015)
  5. Kohsaka, Y., Kanou, M., Takagi, H., Hanaguri, T. and Sasagawa, T.:
    "Imaging ambipolar two-dimensional carriers induced by the spontaneous electric polarization of a polar semiconductor BiTeI"
    Phys. Rev. B 91, 245312 (2015)
  6. Kasahara, S., Watashige, T., Hanaguri, T., Kohsaka, Y., Yamashita, T., Shimoyama, Y., Mizukami, Y., Endo, R., Ikeda, H., Aoyama, K., Terashima, T., Uji, S., Wolf, T., Löhneysen, H. v., Shibauchi, T., and Matsuda, Y.:
    "Field induced superconducting phase of FeSe in the BCS-BEC crossover"
    Proc. Natl. Acad. Sci. USA 111, 16309-16313 (2014)
  7. Fu, Y.-S., Kawamura, M., Igarashi, K., Takagi, H., Hanaguri, T. and Sasagawa,T.:
    "Imaging the two-component nature of Dirac–Landau levels in the topological surface state of Bi2Se3"
    Nature Physics 10, 815–819 (2014).
  8. Okazaki, K., Ito, Y., Ota, Y., Kotani, Y., Shimojima, T., Kiss, T., Watanabe, S., Chen, C.-T., Niitaka, S., and Hanaguri, T.:
    "Superconductivity in an electron band just above the Fermi level: possible route to BCS-BEC superconductivity"
    Scientific Reports 4, 4109 (2014)
  9. Fu, Y.-S., Hanaguri, T., Yamamoto, S., Igarashi, K., Takagi, H., and Sasagawa, T.:
    "Memory effect in a topological surface state of Bi2Te2Se"
    ACS Nano 7, 4105-4110 (2013)
  10. Okazaki, K., Ito, Y., Ota, Y., Kotani, Y., Shimojima, T., Kiss, T., Watanabe, S., Chen, C.-T., Niitaka, S., and Hanaguri, T.:
    "Evidence for a cos(4φ) Modulation of the Superconducting Energy Gap of Optimally Doped FeTe0.6Se0.4 Single Crystals Using Laser Angle-Resolved Photoemission Spectroscopy"
    Phys. Rev. Lett. 109, 237011 (2012)

Lab Members

Principal Investigator

Tetsuo Hanaguri
Team Leader

Core Members

Katsuya Iwaya
Senior Scientist
Yuhki Kohsaka
Senior Scientist
Tadashi Machida
Postdoctoral Researcher
Sukrit Sucharitakul
Postdoctoral Researcher