主要な業績

• 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)
  (JPSJ注目論文：そっくりな元素からなる物質に現れた超伝導と奇妙な絶縁体状態)
  (報道：科学新聞2021年6月25日「同じ電子数・結晶構造なのに全く異なる物性　超伝導体、絶縁体に分かれる　名古屋大が解明」)
  
  
• 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).
  (プレスリリース：磁場により体積が大きく膨張する新機構の発見)
  (報道：マイナビニュース2021年4月12日「名大、磁場を加えると従来にない機構で体積が大きく膨張する物質を発見」)
  
  
• 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).
  (プレスリリース：固体物質における正三角形の分子の形成をとらえた！)
  (Press Release：Unusual electron sharing found in cool crystal)
  (報道：科学新聞2020年7月3日「名古屋大など　正三角形の分子形成　固体物質で初の発見」)
  (紹介記事：academist Journal 2020年7月27日 「固体物質における「正三角形の分子」をとらえた！ – パイロクロア構造に現れた新しいタイプの電子の自己組織化」)
  (解説動画：新学術領域研究「量子液晶」QLCチャンネル）
  
  
• 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).
  (プレスリリース：低温で高い性能を示す熱電変換材料の発見)
  (報道：化学工業日報2017年5月2日「低温でも高い性能　電子機器を局所冷却」他)
  (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)
  (プレスリリース：温めると縮む新材料を発見）
  (報道：朝日新聞2017年1月11日「温めると縮む新材料　開発」他)
  (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)
  (報道：科学新聞2009年4月3日「カゴメ格子に量子スピン配列　新物質を発見」)
  (紹介記事：カゴメ格子上に配列したスピン：銅鉱物ベシニエ石, 岡本佳比古, 広井善二, 固体物理 44, 473 (2009).)
  
  
• 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).
  (紹介記事：RIKEN Research, 4 (1), 6 (2009), "Oxides flex their bonds".)
  
  
• 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).
  (紹介記事：RIKEN Research, 3(4), 3 (2008), "Exotic material keeps frustrated electrons flipping".)
  (Over 400 times cited in Web of Science)
  (Highly Cited Paper in Essential Science Indicators, Thomson Reuters)