Selected Publications

• Superconductivity in Nb2Pd3Te5 and Chemically-Doped Ta2Pd3Te5,
  Naoya Higashihara, Yoshihiko Okamoto*, Yuma Yoshikawa, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, and Koshi Takenaka,
  J. Phys. Soc. Jpn. 90, 063705(1-4) (2021) (arXiv:2105.01886).
  (JPSJ Editors' Choice)
  
  
• Large Magnetic-Field-Induced Strain at the Magnetic Order Transition in Triangular Antiferromagnet AgCrS2,
  Tomoya Kanematsu, Yoshihiko Okamoto*, and Koshi Takenaka,
  Appl. Phys. Lett. 118, 142404(1-5) (2021) (arXiv:2104.03471).
  
  
• High-Mobility Carriers Induced by Chemical Doping in the Candidate Nodal-Line Semimetal CaAgP,
  Yoshihiko Okamoto*, Kazushige Saigusa, Taichi Wada, Youichi Yamakawa, Ai Yamakage, Takao Sasagawa, Naoyuki Katayama, Hiroshi Takatsu, Hiroshi Kageyama, and Koshi Takenaka,
  Phys. Rev. B 102, 115101(1-6) (2020) (arXiv:2008.06188).
  
  
• Regular-Triangle Trimer and Charge Order Preserving the Anderson Condition in the Pyrochlore Structure of CsW2O6,
  Yoshihiko Okamoto*, Haruki Amano, Naoyuki Katayama, Hiroshi Sawa, Kenta Niki, Rikuto Mitoka, Hisatomo Harima, Takumi Hasegawa, Norio Ogita, Yu Tanaka, Masashi Takigawa, Yasunori Yokoyama, Kanji Takehana, Yasutaka Imanaka, Yuto Nakamura, Hideo Kishida, and Koshi Takenaka,
  Nat. Commun. 11, 3144(1-8) (2020) (open access) (arXiv:2006.11053).
  
  
• Large Thermoelectric Power Factor at Low Temperatures in One-Dimensional Telluride Ta4SiTe4,
  Takumi Inohara, Yoshihiko Okamoto*, Youichi Yamakawa, Ai Yamakage, and Koshi Takenaka,
  Appl. Phys. Lett. 110, 183901(1-5) (2017) (arXiv:1705.00404).
  (Press Release: One-Dimensional Crystals for Low-Temperature Thermoelectric Cooling)
  
  
• Colossal Negative Thermal Expansion in Reduced Layered Ruthenate,
  Koshi Takenaka*, Yoshihiko Okamoto, Tsubasa Shinoda, Naoyuki Katayama, and Yuki Sakai,
  Nat. Commun. 8, 14102(1-7) (2017) (open access).
  (Over 100 times cited in Web of Science)
  (Highly Cited Paper in Essential Science Indicators, Thomson Reuters)
  (Press Release: Record-Breaking Material that Contracts When Heated)
  
  
• Thermoelectric Properties of Antiperovskite Calcium Oxides Ca3PbO and Ca3SnO,
  Yoshihiko Okamoto*, Akira Sakamaki, and Koshi Takenaka,
  J. Appl. Phys. 119, 205106(1-5) (2016) (arXiv:1604.06541).
  
  
• Breathing Pyrochlore Lattice Realized in A-site Ordered Spinel Oxides LiGaCr4O8 and LiInCr4O8,
  Yoshihiko Okamoto*, Gøran J. Nilsen, J. Paul Attfield, and Zenji Hiroi,
  Phys. Rev. Lett. 110, 097203(1-5) (2013) (arXiv:1301.6936).
  
  
• Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet,
  Yoshihiko Okamoto*, Hiroyuki Yoshida and Zenji Hiroi,
  J. Phys. Soc. Jpn. 78, 033701(1-4) (2009) (open access) (arXiv:0901.2237).
  (Over 100 times cited in Web of Science)
  (JPSJ Editors' Choice)
  
  
• Band Jahn-Teller Instability and Formation of Valence Bond Solid in a Mixed-Valent Spinel Oxide LiRh2O4,
  Yoshihiko Okamoto, Seiji Niitaka, Masaya Uchida, Takeshi Waki, Masashi Takigawa, Yoshitaka Nakatsu, Akira Sekiyama, Shigemasa Suga, Ryotaro Arita, and Hidenori Takagi,
  Phys. Rev. Lett. 101, 086404(1-4) (2008) (arXiv:0806.2504).
  
  
• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8,
  Yoshihiko Okamoto, Minoru Nohara, Hiroko Aruga-Katori, and Hidenori Takagi,
  Phys. Rev. Lett. 99, 137207(1-4) (2007) (arXiv:0705.2821).
  (Over 400 times cited in Web of Science)
  (Highly Cited Paper in Essential Science Indicators, Thomson Reuters)