Presentations (International)

2025

• Topological Hall Excitonic Insulator GdGaI,
  Ryutaro Okuma,
  The 3rd RIKEN-CEMS ISSP joint workshop, Kashiwa, Japan, December 15th, 2025 (poster)
• Introduction of Center for New Materials Research and Recent Progress on the Development of Novel Cubic Materials,
  Yoshihiko Okamoto,
  The 3rd RIKEN-CEMS ISSP joint workshop, Kashiwa, Japan, December 15th, 2025 (oral)
• Mathematical crystal chemistry: Mixed integer nonlinear programming for crystal structure prediction,
  Ryotaro Koshoji,
  1000-Tesla Workshop: Quest For The Non-Perturbative Magnetic Field Effects In The 1000-Tesla Magnetic Field Region, Kashiwa, Japan, December 6th, 2025 (poster)
• Hydrothermal synthesis and magnetic properties of novel chromium arsenate - NaCr(HAsO₄)₂·H₂O,
  Shinji Matsuura, Ryutaro Okuma, Keita Kojima, and Yoshihiko Okamoto
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Synthesis and Electronic Properties of High-entropy Transition Metal Disulfides,
  Hayato Takano, Eito Takahashi, Kengo Miyata, Daigorou Hirai, and Koshi Takenaka,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Single crystal growth and superconducting properties of hexagonal Sc₆MTe₂ without spatial inversion symmetry,
  Kosuke Yuchi, Daisuke Nishio-Hamane, Kodai Moriyama, Keita Kojima, Ryutaro Okuma, Junichi Yamaura and Yoshihiko Okamoto,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Quadrupolar order in a spin–orbit coupled insulator Ba₂MgReO₆ probed by ultrasonic measurements,
  Toshihiko Muroi, Shunsaku Imajo, Daigorou Hirai, Ruo Hibino, Tatsuya Yanagisawa, Ryutaro Okuma, Jun-ichi Yamaura, Yoshihiko Okamoto, and Zenji Hiroi,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Al₂Ge₂ Tetramer Formation in Topological Semimetal KAlGe,
  Toshiya Ikenobe, Jun-ichi Yamaura, Tamio Oguchi, Ryutaro Okuma, Dyon von Dinter, Takahiro Yamada, Yoshihiko Okamoto, Yoshinori Okada, and Zenji Hiroi,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Mathematical crystal chemistry: A mathematical optimization problem formalization of inorganic structural chemistry for computational prediction of inorganic compounds,
  Ryotaro Koshoji,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 3rd, 2025 (poster)
• Magnetic property of a series of new Zintl phase LiRGa₄ (R=rare earth),
  Keita Nagasawa, Ryutaro Okuma, Daisuke Nishio-Hamane, Keita Kojima, and Yoshihiko Okamoto
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 1st, 2025 (poster)
• Orbital disordered nonmagnetic insulating state in NbSeI,
  Keita Kojima, Hayato Takano, Youichi Yamakawa, Shunsuke Kitou, Ryutaro Okuma, and Yoshihiko Okamoto,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 1st, 2025 (poster)
• Cubic ReSTe as a High-Performance Thermoelectric Material,
  Yoshihiko Okamoto, Haruka Matsumoto, Hiroto Isomura, Keita Kojima, Ryutaro Okuma, Hironori Ohshima, Chul-Ho Lee, and Youichi Yamakawa,
  The 2nd International Symposium on Solid State Chemistry, Matsue, Japan, December 1st, 2025 (poster)
• Hydrothermal synthesis and magnetic properties of novel chromium arsenate - NaCr(HAsO₄)₂·H₂O,
  Shinji Matsuura, Ryutaro Okuma, Keita Kojima, and Yoshihiko Okamoto,
  2025 SNU-ISSP Workshop, Kashiwa, Japan, November 21st, 2025 (poster)
• Synthesis and physical properties of MoSBr-type compounds with molecular orbital degrees of freedom,
  Hayato Takano, Keita Kojima, Jun-ichi Yamaura, Ryutaro Okuma, and Yoshihiko Okamoto,
  2025 SNU-ISSP Workshop, Kashiwa, Japan, November 21st, 2025 (poster)
• Magnetic property of a series of new Zintl phase LiRGa₄ (R=rare earth),
  Keita Nagasawa, Ryutaro Okuma, Jun-ichi Yamaura, and Yoshihiko Okamoto,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 20th, 2025 (poster)
• Al₂Ge₂ excitonic tetramer formation in topological semimetal KAlGe,
  Toshiya Ikenobe, Jun-ichi Yamaura, Tamio Oguchi, Ryutaro Okuma, Dyon Dinter, Takahiro Yamada, Yoshihiko Okamoto, Yoshinori Okada, and Zenji Hiroi,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 20th, 2025 (poster)
• Single crystal growth and superconducting properties of hexagonal Sc₆FeTe₂,
  Kosuke Yuchi, Daisuke Nishio-Hamane, Kodai Moriyama, Keita Kojima, Ryutaro Okuma, Junichi Yamaura and Yoshihiko Okamoto,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 20th, 2025 (poster)
• Mathematical crystal chemistry: Mathamatical formulation of inorganic structural chemistry by mixed integer nonlinear programming,
  Ryotaro Koshoji,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 20th, 2025 (poster)
• Topological Hall Excitonic Insulator GdGaI,
  Ryutaro Okuma,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 20th, 2025 (invite)
• Orbital Physics and Thermoelectric Properties in Tetrahedral Cluster Compounds,
  Yoshihiko Okamoto,
  NIMS-MPI workshop on Materials Aspects of Novel Quantum Systems, Tsukuba, Japan, November 19th, 2025 (invite)
• Molecular Orbital Degeneracy Lifting in a Flat-Band Metal NbSeI,
  Yoshihiko Okamoto, Keita Kojima, Youichi Yamakawa, Ryutaro Okuma, Shunsuke Kitou, Hayato Takano, and Junichi Yamaura
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Mathematical crystal chemistry: Mixed integer nonlinear programming for crystal structure prediction,
  Ryotaro Koshoji,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Single crystal growth and superconducting properties of hexagonal Sc₆FeTe₂,
  Kosuke Yuchi, Daisuke Nishio-Hamane, Kodai Moriyama, Keita Kojima, Ryutaro Okuma, Junichi Yamaura and Yoshihiko Okamoto,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Synthesis and physical properties of MoSBr-type compounds with molecular orbital degrees of freedom,
  Hayato Takano, Keita Kojima, Jun-ichi Yamaura, Ryutaro Okuma, and Yoshihiko Okamoto,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Magnetic property of a series of new Zintl phase LiRGa₄ (R=rare earth),
  Keita Nagasawa, Ryutaro Okuma, Jun-ichi Yamaura, and Yoshihiko Okamoto,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Hydrothermal synthesis and magnetic properties of novel chromium arsenate - NaCr(HAsO₄)₂·H₂O,
  Shinji Matsuura, Ryutaro Okuma, Keita Kojima, and Yoshihiko Okamoto,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Orbital disordered nonmagnetic insulating state in NbSeI,
  Keita Kojima, Hayato Takano, Youichi Yamakawa, Shunsuke Kitou, Ryutaro Okuma, and Yoshihiko Okamoto,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Al₂Ge₂ Excitonic Tetramer Formation in Topological Semimetal KAlGe,
  Toshiya Ikenobe, Tamio Oguchi, Ryutaro Okuma, Dyon Dinter, Takahiro Yamada, Yoshihiko Okamoto, Yoshinori Okada, and Zenji Hiroi,
  The International Workshop on Exotic Quantum Phases due to Unhappy Electrons, Tokyo, Japan, November 13th, 2025 (poster)
• Quadrupolar Order in a Spin–Orbit Coupled Insulator Ba₂MgReO₆ Probed by Ultrasonic Measurements,
  Toshihiko Muroi, Shunsaku Imajo, Daigorou Hirai, Ruo Hibino, Tatsuya Yanagisawa, Ryutaro Okuma, Jun-ichi Yamaura, Yoshihiko Okamoto, and Zenji Hiroi,
  30th International Conference on Low Temperature Physics, Bilbao, Spain, August 9th, 2025 (poster)
• Structural Phase Transition and Flat Band in Cubic NbSeI,
  Keita Kojima, Youichi Yamakawa, Shunsuke Kitou, Ryutaro Okuma, and Yoshihiko Okamoto,
  30th International Conference on Low Temperature Physics, Bilbao, Spain, August 9th, 2025 (poster)
• Synthesis and Superconductivity of Hexagonal Zr₆MBi₂,
  Kosuke Yuchi, Daisuke Nishio-Hamane, Kodai, Moriyama, Keita Kojima, Ryutaro Okuma, Zenji Hiroi, Yoshihiko Okamoto,
  30th International Conference on Low Temperature Physics, Bilbao, Spain, August 9th, 2025 (poster)
• Structural Phase Transition and Flat Band in Cubic NbSeI,
  Keita Kojima, Youichi Yamakawa, Shunsuke Kitou, Ryutaro Okuma, Yoshihiko Okamoto,
  International Conference on Strongly Correlated Electron Systems 2025, Montreal, Canada, July 10th, 2025 (poster)
• Topological Hall Excitonic Insulator GdGaI,
  Ryotaro Okuma,
  Mini-symposium on magnetic semiconductors and nonequilibrium dynamics, Okinawa, Japan, July 3rd, 2025 (invite)
• Orbital-Disordered Insulating State in a Flat Band Metal NbSeI,
  Yoshihiko Okamoto,
  2nd international conference on Quantum Magnetism and Topology, Pohang, Korea, June 18th, 2025 (invited)
• Compass-Model Physics on the Hyperhoneycomb Lattice in the Extreme Spin-Orbit Regime,
  Ryutaro Okuma,
  International Conference on Highly Frustrated Magnetism 2025, University of Toronto, Canada, May 27th, 2025 (invited)
• Orbital-Disordered Insulating State in a Flat Band Metal NbSeI,
  Yoshihiko Okamoto,
  Quantum Synthesis Workshop, Santa Barbara, United States, May 21st, 2025 (invited)
• Al₂Ge₂ Tetramer formation in KAlGe,
  Toshiya Ikenobe, Jun-ichi Yamaura, Takahiro Yamada, Tamio Oguchi, Dyon van Dinter, Ryutaro Okuma, Yoshihiko Okamoto, Yoshinori Okada, and Zenji Hiroi
  Quantum Synthesis Workshop, Santa Barbara, United States, May 19th, 2025 (poster)
• Synthesis and Superconductivity of Hexagonal Zr₆MBi₂,
  Kosuke Yuchi,
  JKT-23, Busan, South-Korea, March 14, 2025 (poster)
• Synthesis and Transport Properties of Ta2Ni3Te5 Single Crystals,
  Hiroto Isomura,
  JKT-23, Busan, South-Korea, March 14, 2025 (poster)
• Self-support Synthesis of inorganic Single Ion Magnets,
  Keita Nagasawa,
  JKT-23, Busan, South-Korea, March 14, 2025 (poster)
• Electronic Self-Organization in the β-Pyrochlore Oxide CsW₂O₆,
  Yoshihiko Okamoto,
  JKT-23, Busan, South-Korea, March 14, 2025 (invited)

2024

• Compass Model Physics on the Hyperhoneycomb β-Na₂PrO₃
  Ryotaro Okuma,
  Correlated Quantum Materials + beyond: Symposium, Kashiwa, Japan, November 26th, 2024 (invited).
• Quadrupolar Order in a Spin-Orbit Coupled Insulator Ba₂MgReO₆ Probed by Ultrasonic Measurements
  Toshihiko Muroi
  Spin-Orbit Entangled Quantum Magnetism, Vienna, Austria, September 24th, 2024 (poster).
• Itinerant Frustration in van der Waals Antiferromagnets
  Ryutaro Okuma
  New Frontiers in Advanced Magnetism 2024, Sapporo, Japan, August 8th, 2024 (invited).
• Hall Effect from Fluctuating Spins in the Kagome Antiferromagnet DyAgGe with Magnetization Plateaus
  Keita Nagasawa
  New Frontiers in Advanced Magnetism 2024, Sapporo, Japan, August 7th, 2024 (poster).
• Quadrupolar Order in a Spin-Orbit Coupled Insulator Ba2MgReO6 Probed by Ultrasonic Measurements
  Toshihiko Muroi
  New Frontiers in Advanced Magnetism 2024, Sapporo, Japan, August 7th, 2024 (poster). (Poster Award)
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yoshihiko Okamoto,
  2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (oral).
• Synthesis and superconductivity of hexagonal Zr₆RuBi₂ without spatial inversion symmetry,
  Kosuke Yuchi, Haruka Matsumoto, Kodai Moriyama, Ryutaro Okuma, Zenji Hiroi, and Yoshihiko Okamoto,
  2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (poster).
• Effect of "trimer frustration" on phase transitions in layered LiVO₂,
  Keita Kojima,
  2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (poster).
• Synthesis and thermoelectric properties of van der Waals crystal Ta₂Ni₃Te₅,
  Hiroto Isomura, Ryutaro Okuma, Junichi Yamaura, and Yoshihiko Okamoto,
  2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (poster).
• Minimum topological magnetism in the Hund's excitonic insulator GdGaI,
  Ryutaro Okuma,
  2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (poster).
• Large Magnetic-Field-Induced Strain in Cr-Based Magnets,
  Yoshihiko Okamoto,
  JKT-22, Kagoshima, Japan, March 15-17, 2024, (invited).
• Noncollinear magnetism from frustrated bond-dependent anisotropic exchange on the f-electron hyperhoneycomb lattice in β-Na₂PrO₃,
  R. Okuma, K. MacFarquharson, R. D. Johnson, D. Voneshen, P. Manuel, and R. Coldea
  American Physical Society March Meeting 2024, Minneapolis, United States, March 4-8, 2024 (oral).
• Superconductivity induced by doping holes in the nodal-line semimetal NaAlGe
  T. Ikenobe, T. Yamada, D. Hirai, H. Yamane, and Z. Hiroi,
  American Physical Society March Meeting 2024, Minneapolis, March 4th (oral).
• Tetrahedral magnetic order by excitonic instability in a van der Waals coupled semiconductor GdGaI,
  R. Okuma, K. Yamagami, Y. Fujisawa, Y. Ihara, and Y. Okada,
  International Conference on Highly Frustrated Magnetism, Chennai, India, January 8-13, 2024 (poster).

2023

• Structural Phase Transition and H-linear Magnetoresistance in Cage-structured Superconductor A₃Co₄Sn₁₃ (A = Ca, La),
  Kodai Moriyama, Chishiro Michioka, Hiroaki Ueda, Wing Chi Yu, Swee Kuan Goh, Kazuyoshi Yoshimura,
  MRM2023/IUMRS-ICA2023, Kyoto, Japan, December 11-16, 2023 (poster).
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yoshihiko Okamoto,
  MRM2023/IUMRS-ICA2023, Kyoto, Japan, December 11-16, 2023 (invited).
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals
  Yoshihiko Okamoto
  The 36th International Symposium on Superconductivity, Takina, Wellington, New Zealand, November 28-30, 2023 (invited).
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yoshihiko Okamoto, Haruka Matsumoto, Kousuke Yuchi, Yusaku Shinoda, Youichi Yamakawa, Daigorou Hirai, and Koshi Takenaka,
  International Conference on Quantum Liquid Crystals 2023, Sapporo, Japan, August 8-10, 2023 (poster).
• Neutron scattering studies of the candidate Kitaev material Na₂PrO₃,
  Ryutaro Okuma, Roger D. Johnson, Pascal Manuel, David Voneshen, and Radu Coldea,
  International Conference on Quantum Liquid Crystals 2023, Sapporo, Japan, August 8-10, 2023 (poster).
• Quantum critical phenomena caused by gradual structural variations in SrCo₂(Ge_1-xP_x)₂,
  Kodai Moriyama, Chishiro Michioka, Hiroaki Ueda, and Kazuyoshi Yoshimura,
  International Conference on Quantum Liquid Crystals 2023, Sapporo, Japan, August 8-10, 2023 (poster).
• Superconductivity in hexagonal zirconium telluride Zr₆MTe₂ (M = Fe, Co),
  Haruka Matsumoto, Zenji Hiroi, and Yoshihiko Okamoto,
  International Conference on Quantum Liquid Crystals 2023, Sapporo, Japan, August 8-10, 2023 (poster).
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yoshihiko Okamoto, Yusaku Shinoda, Haruka Matsumoto, Kousuke Yuchi, Youichi Yamakawa, Daigorou Hirai, and Koshi Takenaka,
  Quantum Materials and Topology 2023, Pohang, Korea, June 27-29, 2023 (poster).
• Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yoshihiko Okamoto,
  The Taiwan-Japan-Korea Symposium on Strongly Correlated Electron Sytems (TJK-21), Hsinchu, Taiwan, Apr. 6-7, 2023 (invited).

• Presentations before Mar. 2022 (Okamoto)