RIKEN Center for Emergent Matter Science Emergent Phenomena Measurement Research Team

Team Leader: Tetsuo Hanaguri (D.Eng.)

Japanese Page

Research Summary

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 Fields

Mathematical & Physical Sciences

Related Research Fields

Interdisciplinary Science & Engineering

Keywords

Superconductivity
Topological quantum phenomena
Scanning probe microscopy

Selected Publications

1. Butler, C.J., Yoshida, M., Hanaguri, T., and Iwasa, Y.:
"Mottness versus unit-cell doubling as the driver of the insulating state in 1T-TaS₂"
Nature Commun. 11, 2477 (2020).
2. Machida, T., Sun, Y., Pyon, S., Takeda, S., Kohsaka, Y., Hanaguri, T., Sasagawa, T., and Tamegai, T.:
"Zero-energy vortex bound state in the superconducting topological surface state of Fe(Se,Te)"
Nature Mater. 18, 811 (2019).
3. Hanaguri, T., Kasahara, S., Böker, J., Eremin, I., Shibauchi, T., and Matsuda, Y.:
"Quantum Vortex Core and Missing Pseudogap in the Multiband BCS-BEC Crossover Superconductor FeSe"
Phys. Rev. Lett. 122, 077001 (2019).
4. Machida, T., Kohsaka, Y., and Hanaguri, T.:
"A scanning tunneling microscope for spectroscopic imaging below 90 mK in magnetic fields up to 17.5 T"
Rev. Sci. Instrum. 89, 093707 (2018).
5. Hanaguri, T., Iwaya, K, Kohsaka, Y., Machida, T., Watashige, T., Kasahara, S., Shibauchi, T., and Matsuda, Y.:
"Two distinct superconducting pairing states divided by the nematic end point in FeSe_1-xS_x"
Science Adv. 4, eaar6419 (2018).
6. Iwaya, K., Kohsaka, Y., Okawa, K., Machida, T., Bahramy, M. S., Hanaguri, T., and Sasagawa, T.:
"Full-gap superconductivity in spin-polarised surface states of topological semimetal β-PdBi₂"
Nature Commun. 8, 976 (2017).
7. Machida, T., Kohsaka, Y., Iwaya, K., Arita, R., Hanaguri, T., Suzuki, R., Ochi, M., and Iwasa, Y.:
"Orbital-dependent quasiparticle scattering interference in 3R-NbS₂"
Phys. Rev. B 96, 075206 (2017).
8. 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).
9. 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).
10. 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).