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

Physics

Related Research Fields

Engineering / Materials Sciences

Research Subjects

  • Surface Dirac electrons in topological insulators
  • Superconducting-gap structures of high-temperature superconductors
  • Development of novel scanning-tunneling-microscopy techniques

Selected Publications

  1. 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).
  2. 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).
  3. 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).
  4. Hanaguri, T., Kitagawa, K., Matsubayashi, K., Mazaki, Y., Uwatoko, Y. and Takagi, H.:
    “Scanning tunneling microscopy/spectroscopy of vortices in LiFeAs”
    Phys. Rev. B 85, 214505 (2012).
  5. Kohsaka, Y., Hanaguri, T., Azuma, M., Takano, M., Davis, J.C. and Takagi, H.:
    “Visualization of the emergence of the pseudogap state and the evolution to superconductivity in a lightly hole-doped Mott insulator”
    Nature Phys. 8, 534-538 (2012).
  6. Hanaguri, T., Igarashi, K., Kawamura, M., Takagi, H. and Sasagawa, T.:
    “Momentum-resolved Landau-level spectroscopy of Dirac surface state in Bi2Se3
    Phys. Rev. B 82, 081305(R) (2010).
  7. Hanaguri, T., Niitaka, S., Kuroki, K. and Takagi, H.:
    “Unconventional s-Wave Superconductivity in Fe(Se,Te)”
    Science 328, 474-476 (2010).
  8. Hanaguri, T., Kohsaka, Y., Ono, M., Maltseva, M., Coleman, P., Yamada, I., Azuma, M., Takano, M. and Ohishi, K.:
    “Coherence Factors in a High-Tc Cuprate Probed by Quasi-particle Scattering off Vortices”
    Science 323, 923-926 (2009).
  9. Hanaguri, T., Kohsaka, Y., Davis, J. C., Lupien, C., Yamada, I., Azuma, M., Takano, M., Ohishi, K., Ono, M. and Takagi, H.:
    “Quasiparticle interference and superconducting gap in Ca2-xNaxCuO2Cl2
    Nature Phys. 3, 865-871 (2007).
  10. Iwaya, K., Satow, S., Hanaguri, T., Shannon, N., Yoshida, Y., Ikeda, S. I., He, J. P., Kaneko, Y., Tokura, Y., Yamada, T. and Takagi, H.:
    “Local Tunneling Spectroscopy across a Metamagnetic Critical Point in the Bilayer Ruthenate Sr3Ru2O7
    Phys. Rev. Lett. 99, 057208 (2007).

Lab Members

Principal Investigator

Tetsuo Hanaguri
Team Leader

Core Members

Katsuya Iwaya
Senior Scientist
Yuhki Kohsaka
Senior Scientist
Tadashi Machida
Postdoctoral Researcher
Tatsuya Watashige
Student Trainee
Kensuke Matsuoka
Student Trainee

Contact information

S406, Chemistry and Materials Physics Building, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Email: hanaguri [at] riken.jp

Related links

Recent research results

August 5, 2016: RIKEN RESEARCH
Mystery solved in superconductor electron patterns
November 13, 2015: RIKEN RESEARCH
Mind the gap!