論文など

2025

• Broken Time-Reversal Symmetry Detected by Tunneling Spectroscopy of Superconducting Pd-doped CaAgP,
  Naoki Matsubara, Rikizo Yano, Kazushige Saigusa, Koshi Takenaka, Yoshihiko Okamoto, Yukio Tanaka, Satoshi Kashiwaya,
  submitted. (arXiv:2412.08335)
• Observation of Current-induced Lattice Distortion in Spin-orbit Coupled Iridium Oxide Ca₅Ir₃O₁₂,
  Keisuke Kadohiro, Hiroki Hanate, Momoka Hayashida, Takumi Hasegawa, Hironori Nakao, Yoshihiko Okamoto, Koji Miyazaki, Satoshi Tsutsui, Kazuyuki Matsuhira*,
  J. Phys. Soc. Jpn. 94, 023601(1-4) (2025). (open access)
• Superconductivity in Hexagonal Zr₆CoAl₂-Type Zr₆RuBi₂ and Zr₆FeBi₂,
  Kosuke Yuchi*, Daisuke Nishio-Hamane, Keita Kojima, Kodai Moriyama, Ryutaro Okuma, and Yoshihiko Okamoto*,
  J. Phys. Soc. Jpn. 94, 013701(1-5) (2025). (arXiv:2410.16684)

2024

• Topological Semimetal KAlGe with Novel Electronic Instability,
  Toshiya Ikenobe*, Takahiro Yamada, Jun-ichi Yamaura, Tamio Oguchi, Ryutaro Okuma, Daigorou Hirai, Hajime Sagayama, Yoshihiko Okamoto, and Zenji Hiroi,
  Chem. Mater., published online. (arXiv:2412.17194)
• Compass-Model Physics on the Hyperhoneycomb Lattice in the Extreme Spin-Orbit Regime,
  Ryutaro Okuma*, Kylie MacFarquharson, Roger D. Johnson, David Voneshen, Pascal Manuel, and Radu Coldea,
  Nat. Commun. 15, 10615(1-8) (2024). (open access)
  (物性研ニュース：蜂の巣をひねって実現した新しい量子状態 ―キタエフ模型を拡張した量子コンパス模型の実現―)
  (Press Release from University of Oxford: Breakthrough discovery in magnetic materials could unlock new quantum states)
• Electronic Self-Organization in the β-Pyrochlore Oxide CsW₂O₆,
  Yoshihiko Okamoto*,
  J. Phys. Soc. Jpn. 93, 111006(1-16) (2024). (open access) (arXiv:2406.13981)
  (JPS Hot Topics: Unlocking Secrets of Novel Charge-Orbital States in Transition-Metal Compounds)
• Selective Synthesis and Crystal Chemistry of Candidate Rare-Earth Kitaev Materials: Honeycomb and Hyperhoneycomb Na₂PrO₃,
  Ryutaro Okuma*, Kylie MacFarquharson, and Radu Coldea,
  Inorg. Chem. 63, 15941-15950 (2024).
• Unbalanced Charge Distribution Stabilized by Orbital Ordering,
  Yoshihiko Okamoto*,
  JPSJ News and Comments 21, 13(1-2) (2024). (open access)
• Pseudo-One-Dimensional Ribbon Chain Cluster Realized under High Pressure in 1T−VSe₂,
  T. Hara, N. Katayama*, S. Kitou, K. Kojima, S. Kawaguchi, and H. Sawa,
  Phys. Rev. B 110, L020103(1-6) (2024).
• Electric Field-Induced Volume Change in Pyro-Vanadate-Phosphates: Toward an Alternative Actuator Architecture,
  K. Takada, J. Shibutani, K .Yagi, F. Ikawa, Y. Yokoyama, D. Hirai, Y. Okamoto, N. Katayama, Y. Uemura, L. M. G. H. Chavas, T. Hatano, A. Fujita, and K. Takenaka*,
  Appl. Phys. Lett. 125, 041903(1-6) (2024).
• Emergent Topological Magnetism in Hund's Excitonic Insulator,
  R. Okuma*, K. Yamagami*, Y. Fujisawa, C. H. Hsu, Y. Obata, N. Tomoda, M. Dronova, K. Kuroda, H. Ishikawa, K. Kawaguchi, K. Aido, K. Kindo, Y. H. Chan, H. Lin, Y. Ihara, T. Kondo, Y. Okada,
  submitted. (arXiv:2405.16781)
• Anisotropic Optical Conductivity Accompanied by a Small Energy Gap in One-Dimensional Thermoelectric Telluride Ta₄SiTe₄,
  Fumiya Matsunaga, Yoshihiko Okamoto*, Yasunori Yokoyama, Kanji Takehana, Yasutaka Imanaka, Yuto Nakamura, Hideo Kishida, Shoya Kawano, Kazuyuki Matsuhira, and Koshi Takenaka,
  Phys. Rev. B 109, L161105(1-6) (2024). (arXiv:2311.13031)
• Nonmagnetic Ground State in RuO₂ Revealed by Muon Spin Rotation,
  M. Hiraishi, H. Okabe, A. Koda, R. Kadono, T. Muroi, D. Hirai, and Z. Hiroi,
  Phys. Rev. Lett. 132, 166702(1-6) (2024).
• 1次元ファンデルワールス結晶Ta₄SiTe₄における熱電効果,
  岡本佳比古*, 山川洋一, 竹中康司,
  固体物理 59, 95-105 (2024).
• クロムテルル化物焼結体に現れる巨大な磁場誘起体積変化,
  岡本佳比古*, 竹中康司,
  FC Report 42, 7-12 (2024).
• Superconductivity in Ternary Zirconium Telluride Zr₆MTe₂ with 3d Transition Metals,
  Haruka Matsumoto, Youichi Yamakawa, Ryutaro Okuma, Daisuke Nishio-Hamane, and Yoshihiko Okamoto*,
  J. Phys. Soc. Jpn. 93, 023705(1-5) (2024). (arXiv:2401.04870)
• Superconductivity in Ternary Germanide ScPdGe and Silicide ScPdSi,
  Yusaku Shinoda, Yoshihiko Okamoto*, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, Daigorou Hirai, and Koshi Takenaka,
  J. Phys. Soc. Jpn. 93, 023701(1-4) (2024). (arXiv:2312.06045)

2023

• Electroactive Actuator Composites Using Volume Change Induced by Insulator-to-Metal Transition in VO₂,
  K. Takenaka*, Y. Mizuno, J. Shibutani, K. Kishida, K. Takada, K. Yagi, Y. Yokoyama, N. Katayama, Y. Okamoto, D. Hirai, T. Hatano, and A. Fujita,
  Appl. Phys. Lett. 123, 231905(1-6) (2023).
  (Featured Article)
• Evidence of Unconventional Superconductivity on the Surface of the Nodal Semimetal CaAg_1-xPd_xP,
  Rikizo Yano*, Shota Nagasaka, Naoki Matsubara, Kazushige Saigusa, Tsuyoshi Tanda, Seiichiro Ito, Ai Yamagake, Yoshihiko Okamoto*, Koshi Takenaka, and Satoshi Kashiwaya*,
  Nat. Commun. 14, 6817(1-6) (2023) (open access).
  (プレスリリース：トポロジカル物質における表面超伝導を発見 ～新しいタイプの非従来型超伝導物質～)
• Superconductivity in Ternary Scandium Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
  Yusaku Shinoda, Yoshihiko Okamoto*, Youichi Yamakawa, Haruka Matsumoto, Daigorou Hirai, and Koshi Takenaka,
  J. Phys. Soc. Jpn. 92, 103701(1-5) (2023) (open access). (arXiv:2304.01444)
  (JPSJ Papers of Editors' Choice)
  (物性研ニュース：さまざまな磁性元素を含む新しい超伝導体ファミリーの発見)
  (JPSJ注目論文：新しい超伝導体ファミリー：異なる磁性元素をもつ7個の新超伝導体の発見)
  (JPS Hot Topics: A New Superconductor Family with Various Magnetic Elements)
• Structural and Electronic Properties of a Triangular Lattice Magnet NaPrTe₂ Compared with NaNdTe₂ and NaTbTe₂,
  Koki Eto, Yoshihiko Okamoto*, Naoyuki Katayama, Hajime Ishikawa, Koichi Kindo, and Koshi Takenaka,
  J. Phys. Soc. Jpn. 92, 094707(1-6) (2023). (arXiv:2307.06516)
• クロム化合物磁性体における磁場誘起歪,
  岡本佳比古*, 竹中康司,
  固体物理 58, 273-282 (2023).
• Signatures of a Magnetic Superstructure Phase Induced by Ultrahigh Magnetic Fields in a Breathing Pyrochlore Antiferromagnet,
  Masaki Gen*, Akihiko Ikeda, Kazushi Aoyama, Harald O. Jeschke, Yuto Ishii, Hajime Ishikawa, Takeshi Yajima, Yoshihiko Okamoto, Xuguang Zhou, Daisuke Nakamura, Shojiro Takeyama, Koichi Kindo, Yasuhiro H. Matsuda, Yoshimitsu Kohama*,
  Proc. Natl. Acad. Sci. 120, e2302756120(1-7) (2023). (arXiv:2301.09509)
  (物性研ニュース：フラストレート磁性体の新たな多段相転移を発見　―未踏超強磁場領域での直接磁化検出―)
• Large Magnetic-Field-Induced Strains in Sintered Chromium Tellurides,
  Yuki Kubota, Yoshihiko Okamoto*, Tomoya Kanematsu, Takeshi Yajima, Daigorou Hirai, and Koshi Takenaka,
  Appl. Phys. Lett. 122, 042404(1-6) (2023). (arXiv:2211.13388)
  (プレスリリース：磁場により体積が大きく膨張する新材料の発見 ―新たなアクチュエータ材料としての応用に期待―)
• Systematic Study on the Role of the Third Zn-Site Element in Zn_2-xMg_xP₂O₇ Showing Giant Negative Thermal Expansion,
  Ryota Kasugai, Yoshifumi Kadowaki, Yasunori Yokoyama, Naoyuki Katayama, Yoshihiko Okamoto, and Koshi Takenaka*,
  Mater. Trans. 64, 638-642 (2023).
• Two-Band Model and Point Contact Spectroscopy of Nodal-Line Semimetal CaAg_0.9Pd_0.1P,
  Naoki Matsubara*, Shota Nagasaka, Rikizo Yano, Kazushige Saigusa, Yusaku Shinoda, Yoshihiko Okamoto, Koshi Takenaka, and Satoshi Kashiwaya,
  JPS Conf. Proc. 38, 011028(1-6) (2023).

2022

• Electronic Properties of Pyrochlore-Type Ca₂Ir₂O₇,
  Yuki Nakayama, Yoshihiko Okamoto*, Daigorou Hirai, and Koshi Takenaka,
  J. Phys. Soc. Jpn. 91, 125002(1-2) (2022). (arXiv:2211.09290)
• Electronic Structure Reconstruction by Trimer Formation in CsW₂O₆ Studied by X-Ray Photoelectron Spectroscopy,
  R. Nakamura, D. Takegami, A. Melendez-Sans, L. H. Tjeng, M. Okawa, T. Miyashino, N. L. Saini, M. Kitamura, D. Shiga, H. Kumigashira, M. Yoshimura, K.-D. Tsuei, Y. Okamoto, and T. Mizokawa,
  Phys. Rev. B 106, 195104(1-6) (2022).
• Electrical-Field-Induced Insulator-to-Metal Transition in Samarium Monosulfides,
  K. Kishida, J. Shibutani, T. Hatano, Y. Yokoyama, N. Katayama, Y. Okamoto, Y. Nakamura, H. Kishida, H. S. Suzuki, K. Takehana, Y. Imanaka, and K. Takenaka*,
  Appl. Phys. Lett. 121, 121901(1-6) (2022).
• Complex Magnetic Phase Diagram with a Small Phase Pocket in a Three-Dimensional Frustrated Magnet CuInCr₄S₈,
  M. Gen*, H. Ishikawa, A. Ikeda, A. Miyake, Z. Yang, Y. Okamoto, M. Mori, K. Takenaka, T. Kurumaji, Y. Tokunaga, T. Arima, M. Tokunaga, K. Kindo, Y. H. Matsuda, Y. Kohama,
  Phys. Rev. Research 4, 033148(1-13) (2022). (arXiv:2112.08990)

• 2022年3月以前の論文(岡本)