Publications

131. 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)

130. 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)

129. 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)

128. 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).

127. 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)

126. Unbalanced Charge Distribution Stabilized by Orbital Ordering,
Yoshihiko Okamoto*,
JPSJ News and Comments 21, 13(1-2) (2024).

125. 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).

124. 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)

123. 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)

122. 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)

121. 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)

120. 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).

119. 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 Editors' Choice)
(JPS Hot Topics: A New Superconductor Family with Various Magnetic Elements)

118. 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, Koshi Takenaka,
J. Phys. Soc. Jpn. 92, 094707(1-6) (2023). (arXiv:2307.06516)

117. 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)

116. 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)
(News: Science Japan "Group led by The Institute for Solid State Physics at The University of Tokyo discovers new material that significantly expands when a magnetic field is applied: Shows promise for new actuators")

115. 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).

114. 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)

113. 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 (2022).

112. 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 (2022).

111. 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 (2022) (arXiv:2112.08990).

110. Large Magnetic-Field-Induced Strain at the Spin-Reorientation Transition in A-Site Ordered Spinel Oxide LiFeCr4O8,
Yoshihiko Okamoto*, Tomoya Kanematsu, Yuki Kubota, Takeshi Yajima, and Koshi Takenaka,
J. Phys. Soc. Jpn. 91, 023710 (2022) (arXiv:2201.01897).

109. Structural Phase Transition and Negative Thermal Expansion in Cu1.8Zn0.2V2–xPxO7 Solid Solutions,
Koshi Takenaka*, Masato Kano, Ryota Kasugai, Kohei Takada, Koki Eto, Yoshifuji Kadowaki, Yasunori Yokoyama, Naoyuki Katayama, and Yoshihiko Okamoto,
Appl. Phys. Express 15, 025504 (2022).

108. Charge-Ordered State Satisfying the Anderson Condition in LiRh2O4 Arising from Local Dimer Order,
Manabu Shiomi, Keita Kojima, Naoyuki Katayama*, Shin Maeda, John A. Schneeloch, Syunsuke Yamamoto, Koudai Sugimoto, Yukinori Ohta, Despina Louca, Yoshihiko Okamoto, Hiroshi Sawa,
Phys. Rev. B 105, L041103 (2022) (arXiv:2112.07118).

107. Structural Phase Transition and Giant Negative Thermal Expansion in Pyrophosphate Zn2-xMgxP2O7,
Y. Kadowaki, R. Kasugai, Y. Yokoyama, N. Katayama, Y. Okamoto, and K. Takenaka*,
Appl. Phys. Lett. 119, 201906 (2021).

106. Giant Negative Thermal Expansion of Polycrystalline Ti2O3 Induced by Microstructural Effects,
Y. Kadowaki, R. Kasugai, Y. Yokoyama, N. Katayama, Y. Okamoto, and K. Takenaka*,
Appl. Phys. Lett. 119, 171901 (2021).

105. 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)
(JPS Hot Topics: Exotic Superconducting States in Transition Metal Tellurides)

104. 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).

103. Emergence of Unconventional Superconductivity in a Two-Dimensional sp Semimetal with Topological Nodal Lines,
Yoshihiko Okamoto,
JPSJ News Comments 18, 05 (2021).

102. Giant Magneto-Volume and Magneto-Caloric Effects of Frustrated Antiferromagnet Mn3GaN under Hydrostatic Pressure,
Koshi Takenaka*, Takuto Sugiura, Yoshifumi Kadowaki, Masaki Ozeki, Yoshihiko Okamoto, and Asaya Fujita,
J. Phys. Soc. Jpn. 90, 044601(1-7) (2021).

101. Fabrication of Metal Matrix Composite Containing Manganese Nitride Showing Giant Negative Thermal Expansion by Compressive Torsion Processing,
Koshi Takenaka*, Kentaro Otsuka, Yoshihiko Okamoto, Yuji Kume, and Makoto Kobashi,
Mater. Trans. 62, 590-595 (2021).

100. Large Thermoelectric Power Factor in Whisker Crystals of Solid Solutions of the One-Dimensional Tellurides Ta4SiTe4 and Nb4SiTe4,
Yuma Yoshikawa, Taichi Wada, Yoshihiko Okamoto*, Yasuhiro Abe, and Koshi Takenaka,
Appl. Phys. Express 13, 125505(1-4) (2020) (arXiv:2011.10162). 

99. Electrical and Thermal Transport Properties of the β-Pyrochlore Oxide CsW2O6,
Yoshihiko Okamoto*, Kenta Niki, Rikuto Mitoka, and Koshi Takenaka,
J. Phys. Soc. Jpn. 89, 124710(1-5) (2020) (arXiv:2010.11404).

98. 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).

97. Annealing Effects on Negative Thermal Expansion Properties of Ball-Milled β-Cu1.8Zn0.2V2O7 Fine Particles,
V. Warne-Lang, M. Sato, M. Ozeki, Y. Kadowaki, Y. Yokoyama, N. Katayama, Y. Okamoto, and K. Takenaka*,
Ceram. Int. 46, 27655-27659 (2020).

96. Sol-Gel Synthesis of Doped Cu2V2O7 Fine Particles Showing Giant Negative Thermal Expansion,
M. Sato, V. Warne-Lang, Y. Kadowaki, N. Katayama, Y. Okamoto, and K. Takenaka*,
AIP Advances 10, 075207(1-6) (2020) (open access) .

95. 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).
(Press Release：Unusual electron sharing found in cool crystal)

94. Thermal Expansion and Volume Magnetostriction in Breathing Pyrochlore Magnets LiACr4X8 (A = Ga, In, X = O, S),
Tomoya Kanematsu, Masaki Mori, Yoshihiko Okamoto*, Takeshi Yajima, and Koshi Takenaka,
J. Phys. Soc. Jpn. 89, 073708(1-4) (2020) (arXiv:2006.06187).

93. Annealing Effect on Local Structure and Negative Thermal Expansion of Antiperovskite Manganese Nitride Fine Particles,
Masaki Ozeki, Victoria Warne-Lang, Hirofumi Tsukasaki, Yuki Sakai, Naoyuki Katayama, Yoshihiko Okamoto, Masaki Azuma, Shigeo Mori, and Koshi Takenaka*,
Appl. Phys. Express 13, 075501(1-5) (2020).

92. Zero-Energy Excitation in Classical Kagome Antiferromagnet NaBa2Mn3F11,
Shohei Hayashida, Hajime Ishikawa, Yoshihiko Okamoto, Tsuyoshi Okubo, Zenji Hiroi, Gøran J. Nilsen, Hannu Mutka, and Takatsugu Masuda,
Phys. Rev. B 101, 214409(1-6) (2020) (arXiv:2006.01526).

91. Real Spin and Pseudospin Topologies in the Noncentrosymmetric Topological Nodal-Line Semimetal CaAgAs,
Hishiro T. Hirose*, Taichi Terashima, Taichi Wada, Yoshitaka Matsushita, Yoshihiko Okamoto, Koshi Takenaka, and Shinya Uji,
Phys. Rev. B 101, 245104(1-10) (2020) (arXiv:2002.05597).

90. Negative Thermal Expansion of beta-Cu1.8Zn0.2V2O7 Ceramic Fine Particles Synthesized by a Spray-Drying Method
Koshi Takenaka*, Muki Sato, Tomohiro Nishikawa, Takuya Omura, Nobuya Yamada, Yasunori Yokoyama, Naoyuki Katayama, and Yoshihiko Okamoto,
J. Japan Inst. Met. Mater. 84, 161-166 (2020).

89. Magnetization Process of the Breathing Pyrochlore Magnet CuInCr4S8 in Ultra-High Magnetic Fields up to 150 T,
Masaki Gen*, Yoshihiko Okamoto, Masaki Mori, Koshi Takenaka, and Yoshimitsu Kohama*,
Phys. Rev. B 101, 054434(1-9) (2020) (arXiv:1910.01315).

88. Spray-Dry Synthesis of β-Cu1.8Zn0.2V2O7 Ceramic Fine Particles Showing Giant Negative Thermal Expansion,
Koshi Takenaka*, Miku Sato, Masaya Mitamura, Yasunori Yokoyama, Naoyuki Katayama, and Yoshihiko Okamoto,
J. Am. Ceram. Soc. 103, 2757-2763 (2020).

87. Effects of Y Substitution on the Electronic Structure and Charge Dynamics of SmS,
Y. Yokoyama*, H. Hasegawa, Y. Mizuno, D. Asai, Y. Okamoto, H. S. Suzuki, K. Takehana, Y. Imanaka, and K. Takenaka,
Phys. Rev. B 100, 245143(1-7) (2019).

86. Superconductivity in PtSbS with a Noncentrosymmetric Cubic Crystal Structure,
Ryosuke Mizutani, Yoshihiko Okamoto*, Hayate Nagaso, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, Shunichiro Kittaka, Yohei Kono, Toshiro Sakakibara, and Koshi Takenaka,
J. Phys. Soc. Jpn. 88, 093709(1-4) (2019) (arXiv:1908.11507).

85. Hole-Doped M4SiTe4 (M = Ta, Nb) as an Efficient p-Type Thermoelectric Material for Low-Temperature Applications,
Yoshihiko Okamoto*, Yuma Yoshikawa, Taichi Wada, and Koshi Takenaka,
Appl. Phys. Lett. 115, 043901(1-5) (2019) (arXiv:1907.10254).
(Editor's Pick)

84. Orbital Transitions and Frustrated Magnetism in the Kagome-Type Copper Mineral Volborthite,
Zenji Hiroi*, Hajime Ishikawa, Hiroyuki Yoshida, Jun-ichi Yamaura, and Yoshihiko Okamoto,
Inorg. Chem. 58, 11949-11960 (2019).

83. Rattling Behavior in a Simple Perovskite NaWO3,
Yuya Ikeuchi, Hiroshi Takatsu, Cedric Tassel, Craig M. Brown, Taito Murakami, Yuki Matsumoto, Yoshihiko Okamoto, and Hiroshi Kageyama*,
Inorg. Chem. 58, 6790-6795 (2019). 

82. Valence Fluctuations and Giant Isotropic Negative Thermal Expansion in Sm1-xRxS (R = Y, La, Ce, Pr, Nd),
D. Asai, Y. Mizuno, H. Hasegawa, Y. Yokoyama, Y. Okamoto, N. Katayama, H. S. Suzuki, Y. Imanaka, and K. Takenaka*,
Appl. Phys. Lett. 114, 141902(1-5) (2019).

81. Giant Isotropic Negative Thermal Expansion in Y-Doped Samarium Monosulfides by Intra-Atomic Charge Transfer,
Koshi Takenaka*, Daigo Asai, Ryoichi Kaizu, Yosuke Mizuno, Yasunori Yokoyama, Yoshihiko Okamoto, Naoyuki Katayama, Hiroyuki S. Suzuki, and Yasutaka Imanaka,
Sci. Rep. 9, 122(1-8) (2019). (open access)

80. Ultra-High Magnetic Field Magnetic Phases up to 130 T in a Breathing Pyrochlore Antiferromagnet LiInCr4O8,
Masaki Gen, Daisuke Nakamura, Yoshihiko Okamoto, and Shojiro Takeyama*,
J. Magn. Magn. Mater. 473, 387-393 (2019).

79. Microstructural Effects on Negative Thermal Expansion Extending over a Wide Temperature Range in β-Cu1.8Zn0.2V2O7,
N. Katayama*, K. Otsuka, M. Mitamura, Y. Yokoyama, Y. Okamoto, and K. Takenaka,
Appl. Phys. Lett. 113, 181902(1-5) (2018).

78. Extended Operating Temperature Window of Giant Negative Thermal Expansion in Sn-Doped Ca2RuO4,
K. Takenaka*, N. Inoue, Y. Mizuno, Y. Okamoto, N. Katayama, Y. Sakai, T. Nishikubo, and M. Azuma,
Appl. Phys. Lett. 113, 071902(1-5) (2018).

77. Inelastic Neutron Scattering Study of the Spin Dynamics in the Breathing Pyrochlore System LiGa0.95In0.05Cr4O8,
Yu Tanaka, Rafal Wawrzynczak*, Manh Duc Le, Tatiana Guidi, Yoshihiko Okamoto, Takeshi Yajima, Zenji Hiroi, Masashi Takigawa, and Gøran J. Nilsen*,
J. Phys. Soc. Jpn. 87, 073710(1-4) (2018).

76. Large Thermoelectric Power Factor in One-Dimensional Telluride Nb4SiTe4 and Substituted Compounds,
Yoshihiko Okamoto*, Taichi Wada, Youichi Yamakawa, Takumi Inohara, and Koshi Takenaka,
Appl. Phys. Lett. 112, 173905(1-5) (2018) (arXiv:1804.09867).

75. Magnetic and Structural Properties of A-Site Ordered Chromium Spinel Sulfides: Alternating Antiferromagnetic and Ferromagnetic Interactions in the Breathing Pyrochlore Lattice,
Yoshihiko Okamoto*, Masaki Mori, Naoyuki Katayama, Atsushi Miyake, Masashi Tokunaga, Akira Matsuo, Koichi Kindo, and Koshi Takenaka,
J. Phys. Soc. Jpn. 87, 034709(1-8) (2018) (arXiv:1801.07354).

74. Magnetic State Selected by Magnetic Dipole Interaction in the Kagome Antiferromagnet NaBa2Mn3F11,
Shohei Hayashida, Hajime Ishikawa, Yoshihiko Okamoto, Tsuyoshi Okubo, Zenji Hiroi, Maxim Avdeev, Pascal Manuel, Masato Hagihala, Minoru Soda, and Takatsugu Masuda,
Phys. Rev. B, 97, 054411(1-7) (2018) (arXiv:1712.06740).

73. Observation of Dirac-Like Energy Band and Ring-Torus Fermi Surface Associated with the Nodal Line in Topological Insulator CaAgAs,
Daichi Takane, Kosuke Nakayama, Seigo Souma, Taichi Wada, Yoshihiko Okamoto, Koshi Takenaka, Youichi Yamakawa, Ai Yamakage, Taichi Mitsuhashi, Koji Horiba, Hiroshi Kumigashira, Takashi Takahashi, and Takafumi Sato*,
npj Quamtum Mater. 3, 1(1-6) (2018) (open access) (arXiv:1708.06874).

72. Direct Visualization of Orbital-Flipping in Volborthite by Charge Density Analysis using Detwinned Data,
Kento Sugawara, Kunihisa Sugimoto*, Tatsuya Fujii, Takafumi Higuchi, Naoyuki Katayama, Yoshihiko Okamoto, and Hiroshi Sawa*,
J. Phys. Soc. Jpn. 87, 024601(1-5) (2018).

71. Spin Dynamics in the High-Field Phases of Volborthite,
M. Yoshida*, K. Nawa, H. Ishikawa, M. Takigawa, M. Jeong, S. Kramer, M. Horvatic, C. Berthier, K. Matsui, T. Goto, S. Kimura, T. Sasaki, J. Yamaura, H. Yoshida, Y. Okamoto, and Z. Hiroi,
Phys. Rev. B, 96, 180413(1-5) (2017) (arXiv:1602.04028).
(PRB Editors' Suggestion)

70. Collinear Spin-Density-Wave Order and Anisotropic Spin Fluctuations in the Frustrated J1-J2 Chain Magnet NaCuMoO4(OH),
Kazuhiro Nawa*, Makoto Yoshida, Yoshihiko Okamoto, Masashi Takigawa, and Zenji Hiroi,
Phys. Rev. B, 96, 174433(1-9) (2017) (arXiv:1711.03175).

69. Giant Negative Thermal Expansion in Fe-Doped Layered Ruthenate Ceramics,
Koshi Takenaka, Tsubasa Shinoda, Naruhiro Inoue, Yoshihiko Okamoto, Naoyuki Katayama, Yuki Sakai, Takumi Nishikubo, and Masaki Azuma,
Appl. Phys. Express 10, 115501(1-4) (2017).
(Spotlights 2017)

68. Classical Spin Nematic Transition in LiGa0.95In0.05Cr4O8,
R. Wawrzynczak*, Y. Tanaka*, M. Yoshida, Y. Okamoto, P. Manuel, N. Casati, Z. Hiroi, M. Takigawa, and G. J. Nilsen*,
Phys. Rev. Lett. 119, 087201(1-5) (2017) (arXiv:1706.08409).

67. Phase Diagram of Multiferroic KCu3As2O7(OD)3,
Gøran J. Nilsen*, Virginie Simonet, Claire V. Colin, Ryutaro Okuma, Yoshihiko Okamoto, Masashi Tokunaga, Thomas C. Hansen, Dmitry D. Khalyavin, and Zenji Hiroi,
Phys. Rev. B 95, 214415(1-10) (2017) (arXiv:1702.03268).

66. Crossing-Line-Node Semimetals: General Theory and Application to Rare-Earth Trihydrides,
Shingo Kobayashi, Youichi Yamakawa, Ai Yamakage, Takumi Inohara, Yoshihiko Okamoto, and Yukio Tanaka,
Phys. Rev. B 95, 245208(1-15) (2017) (arXiv:1703.03587).

65. 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)

64. 物質探索のための5d遷移金属化合物の結晶化学 (J-Physics 若手夏の学校：テキスト),
岡本佳比古,
物性研究・電子版 6, 061206(1-31) (2017) (open access).

63. Magnetic Transitions under Ultrahigh Magnetic Fields of up to 130 T in the Breathing Pyrochlore Antiferromagnet LiInCr4O8,
Yoshihiko Okamoto*, Daisuke Nakamura, Atsushi Miyake, Shojiro Takeyama, Masashi Tokunaga, Akira Matsuo, Koichi Kindo, and Zenji Hiroi,
Phys. Rev. B 95, 134438(1-5) (2017) (arXiv:1704.02784).

62. 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)

61. Low Carrier Density Metal Realized in Candidate Line-Node Dirac Semimetals CaAgP and CaAgAs,
Yoshihiko Okamoto*, Takumi Inohara, Ai Yamakage, Youichi Yamakawa, and Koshi Takenaka,
J. Phys. Soc. Jpn. 85, 123701(1-5) (2016) (open access) (arXiv:1611.00490).
(Most Cited Articles in 2017 from Vol. 85 (2016))

60. Synthesis and Superconducting Properties of a Hexagonal Phosphide ScRhP,
Takumi Inohara, Yoshihiko Okamoto*, Youichi Yamakawa, and Koshi Takenaka,
J. Phys. Soc. Jpn. 85, 094706(1-5) (2016) (arXiv:1608.05228).

59. Terahertz ESR Measurements of Magnetically Aligned NaCuMoO4(OH),
Yoko Kitahara, Shigeo Hara, Takahiro Sakurai, Susumu Okubo, Hitoshi Ohta, Fumiko Kimura, Tsunehisa Kimura, Kazuhiro Nawa, Yoshihiko Okamoto, and Zenji Hiroi,
J. Jpn. Soc. Infrared Science and Technology 26, 56-61 (2016).

58. 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).

57. Superconductivity in the Hexagonal Ternary Phosphide ScIrP,
Yoshihiko Okamoto*, Takumi Inohara, Youichi Yamakawa, Ai Yamakage, and Koshi Takenaka,
J. Phys. Soc. Jpn. 85, 013704(1-5) (2016) (arXiv:1512.03864).

56. Line-Node Dirac Semimetal and Topological Insulating Phase in Noncentrosymmetric Pnictides CaAgX (X = P, As),
Ai Yamakage, Youichi Yamakawa, Yukio Tanaka, and Yoshihiko Okamoto,
J. Phys. Soc. Jpn. 85, 013708(1-4) (2016) (open access) (arXiv:1510.00202).
(Over 100 times cited in Web of Science)
(Highly Cited Paper in Essential Science Indicators, Thomson Reuters)
(Most Cited Articles in 2017 from Vol. 85 (2016))

55. Large Diamagnetic Susceptibility from Petit Fermi Surfaces in LaV2Al20,
Takahiro Hirose*, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi,
J. Phys. Soc. Jpn. 84, 113701(1-5) (2015).

54. On the Microscopic Dynamics of the 'Einstein Solids' AlV2Al20 and GaV2Al20, and of YV2Al20: A Benchmark System for 'Rattling' Excitations,
Micael Marek Koza*, Hannu Mutka, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi,
Phys. Chem. Chem. Phys. 17(38) 24837-24850 (2015)(open access).

53. Frozen State and Spin Liquid Physics in Na4Ir3O8: an NMR Study,
A. C. Shockley*, F. Bert, J-C. Orain, Y. Okamoto, and P. Mendels*,
Phys. Rev. Lett. 115, 047201(1-5) (2015) (arXiv:1505.04815).

52. One-Third Magnetization Plateau with a Preceding Novel Phase in Volborthite,
H. Ishikawa, M. Yoshida, K. Nawa, M. Jeong, S. Krämer, M. Horvatic, C. Berthier, M. Takigawa, M. Akaki, A. Miyake, M. Tokunaga, K. Kindo, J. Yamaura, Y. Okamoto, and Z. Hiroi,
Phys. Rev. Lett. 114, 227202(1-5) (2015) (arXiv:1506.00076).

51. Orbital Arrangements and Magnetic Interactions in the Quasi-One-Dimensional Cuprates ACuMoO4(OH) (A = Na, K),
Kazuhiro Nawa*, Takeshi Yajima, Yoshihiko Okamoto, and Zenji Hiroi,
Inorg. Chem. 54(11), 5566-5570 (2015) (arXiv:1505.05332).

50. Complex Magnetostructural Order in the Frustrated Spinel LiInCr4O8,
Gøran J. Nilsen*, Yoshihiko Okamoto, Takatsugu Masuda, Juan Rodriguez-Carvajal, Hannu Mutka, Thomas Hansen, and Zenji Hiroi,
Phys. Rev. B 91, 174435(1-8) (2015).
(PRB Editors' Suggestion)

49. Spinodally Decomposed Nanostructures in a TiO2-VO2 Crystal,
Zenji Hiroi*, Toru Yoshida, Jun-ichi Yamaura, and Yoshihiko Okamoto,
APL Mater. 3, 062508(1-8) (2015) (open access).

48. Magnetic Phase Diagram of the Breathing Pyrochlore Antiferromagnet LiGa1-xInxCr4O8,
Yoshihiko Okamoto*, Gøran J. Nilsen, Taishi Nakazono, and Zenji Hiroi,
J. Phys. Soc. Jpn. 84, 043707(1-5) (2015) (arXiv:1503.08902).

47. Lifshitz Metal-Insulator Transition Induced by the All-in/All-out Magnetic Order in the Pyrochlore Oxide Cd2Os2O7,
Zenji Hiroi*, Jun-ichi Yamaura, Takahiro Hirose, Issei Nagashima, and Yoshihiko Okamoto,
APL Mat. 3, 041501(1-11) (2015) (open access) (arXiv:1502.00191).

46. Novel Phase Transitions in the Breathing Pyrochlore Lattice: 7Li-NMR on LiInCr4O8 and LiGaCr4O8,
Yu Tanaka, Makoto Yoshida, Masashi Takigawa, Yoshihiko Okamoto, and Zenji Hiroi,
Phys. Rev. Lett. 113, 227204(1-5) (2014) (arXiv:1411.1577).

45. NaCuMoO4(OH) as a Candidate Frustrated J1-J2 Chain Quantum Magnet,
Kazuhiro Nawa*, Yoshihiko Okamoto, Akira Matsuo, Koichi Kindo, Yoko Kitahara, Syota Yoshida, Shohei Ikeda, Shigeo Hara, Takahiro Sakurai, Susumu Okubo, Hitoshi Ohta, and Zenji Hiroi,
J. Phys. Soc. Jpn. 83, 103702(1-5) (2014) (arXiv:1409.1310).

44. Thermoelectric Properties of Sr and Mg Double-Substituted LaCoO3 at Room Temperature,
Arreerat Jiamprasertboon, Yoshihiko Okamoto, Zenji Hiroi, and Theeranun Siritanon*,
Ceram. Int., 40, 12729-12735 (2014).

43. Helical Order and Multiferroicity in the S = 1/2 Quasi-Kagome System KCu3As2O7(OD)3,
G. J. Nilsen*, Y. Okamoto, H. Ishikawa, V. Shimonet, C. V. Colin, A. Cano, L. C. Chapon, T. Hansen, H. Mutka, and Z. Hiroi,
Phys. Rev. B 89, 140412(1-5) (2014) (arXiv:1404.3107).

42. Kagome-Triangular Lattice Antiferromagnet NaBa2Mn3F11,
Hajime Ishikawa*, Tsuyoshi Okubo, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys. Soc. Jpn. 83, 043703(1-5) (2014) (arXiv:1403.2128).

41. Novel K Rattling: A New Route to Thermoelectric Materials?,
Elvis Shoko*, Yoshihiko Okamoto, Gordon J. Kearley, Vanessa K. Peterson, Gordon J. Thorogood,
J. Appl. Phys. 115, 033703(1-8) (2014) (arXiv:1310.8382).

40. Spinodal Decomposition in the TiO2-VO2 System,
Zenji Hiroi*, Hiroaki Hayamizu, Toru Yoshida, Yuji Muraoka, Yoshihiko Okamoto, Jun-ichi Yamaura, and Yutaka Ueda,
Chem. Mater. 25, 2202-2210 (2013) (arXiv:1306.2444).

39. Magnetic Properties of the Spin-1/2 Deformed Kagome Antiferromagnet Edwardsite,
Hajime Ishikawa*, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys. Soc. Jpn. 82, 063710(1-5) (2013) (arXiv:1305.2477).

38. Pressure Effects on Rattling and Superconductivity in the Einstein Solids,
Yoichi Ikeda*, Yasuhiro Kawasaki, Takafumi Shinohara, Shingo Araki, Tatsuo C. Kobayashi, Atsushi Onosaka, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi,
J. Phys. Soc. Jpn. 82, 063707(1-4) (2013).

37. 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).
(Over 100 times cited in Web of Science)

36. YCr6Ge6 as a Candidate Compound for a Kagome Metal,
Yui Ishii*, Hisatomo Harima, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi,
J. Phys. Soc. Jpn. 82, 023705(1-4) (2013) (arXiv:1212.1976).

35. Magnetic Order in the Spin-1/2 Kagome Antiferromagnet Vesignieite,
Makoto Yoshida*, Yoshihiko Okamoto, Hiroyuki Yoshida, Masashi Takigawa, and Zenji Hiroi,
J. Phys. Soc. Jpn. 82, 013702(1-4) (2013) (arXiv:1209.4693).

34. Large Diamagnetism of AV2Al20 (A = Y and La),
Atsushi Onosaka, Yoshihiko Okamoto, Jun-ichi Yamaura, Takahiro Hirose, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 81, 123702(1-4) (2012) (arXiv:1211.0066).

33. Rattling and Superconducting Properties of the Cage Compound GaxV2Al20,
Zenji Hiroi, Atsushi Onosaka, Yoshihiko Okamoto, Jun-ichi Yamaura, and Hisatomo Harima,
J. Phys. Soc. Jpn. 81, 124707(1-11) (2012) (open access) (arXiv:1210.6461).

32. Giant Phonon Softening and Enhancement of Superconductivity by Phosphorus Doping of BaNi2As2,
K. Kudo*, M. Takasuga, Y. Okamoto, Z. Hiroi, and M. Nohara,
Phys. Rev. Lett. 109, 097002(1-5) (2012) (arXiv:1204.4958).

31. A Novel Crystal Polymorph of Volborthite Cu3V2O7(OH)2 2H2O,
Hajime Ishikawa*, Jun-ichi Yamaura, Yoshihiko Okamoto, Hiroyuki Yoshida, Gøran J. Nilsen, and Zenji Hiroi,
Acta Cryst. C68, i41-i44 (2012) (arXiv:1209.3162).

30. Crystal Chemistry and Magnetic Properties of Manganese Zinc Alloy "YMn2Zn20" Comprising a Mn Pyrochlore Lattice,
Yoshihiko Okamoto*, Takeshi Shimizu, Jun-ichi Yamaura, and Zenji Hiroi,
J. Solid State Chem. 191, 246-256 (2012) (arXiv:1203.4887).

29. Orbital Switching in a Frustrated Magnet,
Hiroyuki Yoshida*, Jun-ichi Yamaura, Masaaki Isobe, Yoshihiko Okamoto, Gøran J. Nilsen, and Zenji Hiroi,
Nat. Commun. 3, 860(1-5) (2012).

28. The Spin Dynamics in Distorted Kagome Lattices: a Comparative Raman Study,
D. Wulferding*, P. Lemmens, Hiroyuki Yoshida, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys.: Condens. Matter, 24, 185602(1-5) (2012) (arXiv:1111.2167).

27. Distorted Kagome Lattice Generated by a Unique Orbital Arrangement in the Copper Mineral KCu3As2O7(OH)3,
Yoshihiko Okamoto*, Hajime Ishikawa, Gøran J. Nilsen, and Zenji Hiroi,
J. Phys. Soc. Jpn. 81, 033707(1-4) (2012) (arXiv:1202.2913).

26. High-Field Phase Diagram and Spin Structure of Volborthite Cu3V2O7(OH)2 2H2O,
Makoto Yoshida*, Masashi Takigawa*, Steffen Krämer, Sutirtha Mukhopadhyay, Mladen Horvatic, Claude Berthier, Hiroyuki Yoshida, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys. Soc. Jpn. 81, 024703(1-9) (2012) (open access) (arXiv:1110.0260).

25. Superconductivity in the Einstein Solid AxV2Al20 (A = Al and Ga),
Atsushi Onosaka, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 81, 023703(1-4) (2012) (arXiv:1112.5229).

24. Superconductivity and Rattling under High Pressure in the β-Pyrochlore Oxide RbOs2O6,
Nao Takeshita*, Hiroki Ogusu, Jun-ichi Yamaura, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys. Soc. Jpn. 80, 104708(1-8) (2011) (arXiv:1109.5422).

23. Heterogeneous Spin State in the Field-Induced Phase of Volborthite as Seen via 51V Nuclear Magnetic Resonance,
Makoto Yoshida, Masashi Takigawa, Hiroyuki Yoshida, Yoshihiko Okamoto, and Zenji Hiroi,
Phys. Rev. B 84, 020410(1-4) (2011) (arXiv:1103.6137).

22. A Magnetic Transition Probed by the Ce Ion in Square-Lattice Antiferromagnet CeMnAsO,
Yuto Tsukamoto, Yoshihiko Okamoto, Kazuyuki Matsuhira, Myung-Hwan Whangbo, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 80, 094708(1-5) (2011) (arXiv:1108.0121).

21. Magnetization Plateaus of Spin-1/2 Kagome Antiferromagnets Volborthite and Vesignieite,
Yoshihiko Okamoto*, Masashi Tokunaga, Hiroyuki Yoshida, Akira Matsuo, Koichi Kindo, and Zenji Hiroi,
Phys. Rev. B 83, 180407(R)(1-4) (2011) (arXiv:1103.3116).
(PRB Editors' Suggestion)

20. Hard X-Ray Photoelectron Spectroscopy of Metal-Insulator Transition in LiRh2O4,
Y. Nakatsu, A. Sekiyama, S. Imada, Y. Okamoto, S. Niitaka, H. Takagi, A. Higashiya, M. Yabashi, K. Tamasaku, T. Ishikawa, and S. Suga,
Phys. Rev. B 83, 115120(1-4) (2011).

19. Superconducting and Structural Transitions in the β-Pyrochlore Oxide KOs2O6 under High Pressure,
Hiroki Ogusu, Nao Takeshita, Koichi Izawa, Jun-ichi Yamaura, Yasuo Ohishi, Satoshi Tsutsui, Yoshihiko Okamoto, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 79, 114710(1-6) (2010) (arXiv:1009.0355).

18. Itinerant-Electron Magnet of the Pyrochlore Lattice: Indium-Doped YMn2Zn20,
Yoshihiko Okamoto*, Takeshi Shimizu, Jun-ichi Yamaura, Yoko Kiuchi, and Zenji Hiroi,
J. Phys. Soc. Jpn. 79, 093712(1-4) (2010) (arXiv:1008.0835).
(JPSJ Editors' Choice)

17. Thermodynamic Properties of the Kagome Lattice in Volborthite,
Satoshi Yamashita, Tomoya Moriura, Yasuhiro Nakazawa*, Hiroyuki Yoshida, Yoshihiko Okamoto, and Zenji Hiroi,
J. Phys. Soc. Jpn. 79, 083710(1-4) (2010) (arXiv:1008.1835).

16. Resonant Photoemission Spectroscopy of Layered Triangular Lattices Ag2MO2 (M = Ni and Mn); Evidence for M 3d States at Fermi Level,
Ritsuko Eguchi*, Hiroyuki Yoshida, Yoshihiko Okamoto, Ashish Chainani, Masaharu Matsunami, Yukiaki Ishida, Masaki Oura, Yasunori Senba, Haruhiko Ohashi, Shik Shin, and Zenji Hiroi,
J. Phys. Soc. Jpn. 79, 023704(1-4) (2010).

15. High-Field ESR Measurements of S = 1/2 Kagome Lattice Antiferromagnet BaCu3V2O8(OH)2,
Wei-min Zhang, Hitoshi Ohta, Susumu Okubo, Masashi Fujisawa, Takahiro Sakurai, Yoshihiko Okamoto, Hiroyuki Yoshida, and Zenji Hiroi,
J. Phys. Soc. Jpn. 79, 023708(1-4) (2010) (open access) (arXiv:0912.4335).

14. Discontinuous Lifshitz Transition Achieved by Band-Filling Control in NaxCoO2,
Yoshihiko Okamoto, Atsushi Nishio, and Zenji Hiroi,
Phys. Rev. B 81, 121102(R)(1-4) (2010) (arXiv:1002.4282).

13. Evidence for Oxygen Holes due to d-p Rehybridization in Thermoelectric Sr1-xRh2O4,
Y. Ishida, T. Baba, R. Eguchi, M. Matsunami, M. Taguchi, A. Chainani, Y. Senba, Y. Okamoto, H. Takagi, and S. Shin,
Phys. Rev. B 80, 081103(R)(1-4) (2009) (arXiv:0907.5455).

12. Phase Diagram and Spin Dynamics in Volborthite with a Distorted Kagome Lattice,
Makoto Yoshida, Masashi Takigawa, Hiroyuki Yoshida, Yoshihiko Okamoto, and Zenji Hiroi,
Phys. Rev. Lett. 103, 077207(1-4) (2009) (arXiv:0906.2846).

11. Rattling-Induced Superconductivity in the β-Pyrochlore Oxides AOs2O6,
Yohei Nagao, Junichi Yamaura, Hiroki Ogusu, Yoshihiko Okamoto, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 78, 064702(1-21) (2009) (open access) (arXiv:0906.4656).
(JPSJ Editors' Choice)

10. Magnetization "Steps" on a Kagome Lattice in Volborthite,
Hiroyuki Yoshida, Yoshihiko Okamoto, Takashi Tayama, Toshiro Sakakibara, Masashi Tokunaga, Akira Matsuo, Yasuo Narumi, Koichi Kindo, Makoto Yoshida, Masashi Takigawa and Zenji Hiroi*,
J. Phys. Soc. Jpn. 78, 043704(1-4) (2009) (arXiv:0902.3028).

9. Structure and Photoemission Spectroscopy of Strain-Controlled Metal-Insulator Transition in NdNiO3 Thin Films,
R. Eguchi*, Y. Okamoto, Z. Hiroi, S. Shin, A. Chainani, Y. Tanaka, M. Matsunami, Y. Tanaka, Y. Nishino, K. Tamasaku, M. Yabashi and T. Ishikawa,
J. Appl. Phys. 105, 056103(1-3) (2009).

8. 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)

7. 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).

6. Unique Phase Transition on Spin-2 Triangular Lattice of Ag2MnO2,
Hiroyuki Yoshida, Sascha Ahlert, Martin Jansen, Yoshihiko Okamoto, Jun-ichi Yamaura, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 77, 074719(1-8) (2008) (arXiv:0805.3749).

5. 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)

4. Superconductivity in Rh2Ga9 and Ir2Ga9 without Inversion Symmetry,
Takeshi Shibayama, Minoru Nohara*, Hiroko Aruga-Katori, Yoshihiko Okamoto, Zenji Hiroi, and Hidenori Takagi,
J. Phys. Soc. Jpn. 76, 073708(1-4) (2007) (arXiv:0706.0577).

3. Precise Control of Band Filling in NaxCoO2,
Daisuke Yoshizumi, Yuji Muraoka, Yoshihiko Okamoto, Yoko Kiuchi, Jun-Ichi Yamaura, Masahito Mochizuki, Masao Ogata, and Zenji Hiroi*,
J. Phys. Soc. Jpn. 76, 063705(1-4) (2007) (arXiv:0704.1065).

2. Metal-Insulator Transition in a Pyrochlore-type Ruthenium Oxide Hg2Ru2O7,
Ayako Yamamoto*, Peter A. Sharma, Yoshihiko Okamoto, Aiko Nakao, Hiroko Aruga-Katori, Seiji Niitaka, Daisuke Hashizume, and Hidenori Takagi,
J. Phys. Soc. Jpn. 76, 043703(1-4) (2007) (arXiv:cond-mat/0702411).

1. Correlated Metallic Phase in a Doped Band Insulator Sr1-xRh2O4,
Yoshihiko Okamoto*, Minoru Nohara*, Fumiko Sakai and Hidenori Takagi,
J. Phys. Soc. Jpn. 75, 023704(1-4) (2006).

Proceedings

10. 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).

9. Electronic Properties of BaPtP with a Noncentrosymmetric Cubic Crystal Structure,
Yoshihiko Okamoto, Ryosuke Mizutani, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, and Koshi Takenaka,
JPS Conf. Proc., 29, 011001(1-6) (2020) (arXiv:1911.02231) (open access).

8. Crystal Growth of a Frustrated J1-J2 Chain Magnet NaCuMoO4(OH),
Kazuhiro Nawa, Yoshihiko Okamoto, and Zenji Hiroi,
Journal of Physics: Conference Series, 828, 012005 (2017) (open access).

7. Spin Dynamics of Mn Pyrochlore Lattice in YMn2Zn20-xInx,
M. Miyazaki, R. Kadono, M. Hiraishi, I. Yamauchi, A. Koda, K. M. Kojima, I. Kawasaki, I. Watanabe, Y. Okamoto, and Zenji Hiroi,
Journal of Physics: Conference Series, 551, 012019 (2014) (open access).

6. Novel Magnetic Order in the Kagome Lattice of Volborthite,
Zenji Hiroi, Hiroyuki Yoshida, Yoshihiko Okamoto, and Makoto Yoshida,
Journal of Physics: Conference Series, 320, 012003 (2011) (open access).

5. Spin Dynamics of S = 1/2 Kagome Lattice Antiferromagnets Observed by High-Field ESR,
Hitoshi Ohta, Wei-min Zhang, Susumu Okubo, Masashi Fujisawa, Takahiro Sakurai, Yoshihiko Okamoto, Hiroyuki Yoshida, and Zenji Hiroi,
Physica Status Solidi B, 247, 679-681 (2010).

4. High-Pressure Resistivity Measurements on the beta-Pyrochlore Oxide KOs2O6,
Hiroki Ogusu, Nao Takeshita, Jun-ichi Yamaura, Yoshihiko Okamoto, and Zenji Hiroi,
Physica C, 470, S738 (2010).

3. Synthesis and Physical Properties of CeFe1-xMxAsO (M = Mn, Co),
Yuto Tsukamoto, Yoshihiko Okamoto and Zenji Hiroi,
Physica C, 470, S445 (2010).

2. S = 1/2 Kagosme Lattice Antiferromagnet Cu3V2O7(OH)2 2H2O Studied by High Field ESR,
H. Ohta, W. Zhang, S. Okubo, M. Tomoo, M. Fujisawa, H. Yoshida, Y. Okamoto and Z. Hiroi,
Journal of Physics: Conference Series, 145, 012010(1-4) (2009) (open access).

1. Spin-1/2 Kagome Compounds: Volborthite vs Herbertsmithite,
Zenji Hiroi, Hiroyuki Yoshida, Yoshihiko Okamoto and Masashi Takigawa,
Journal of Physics: Conference Series, 145, 012002(1-8) (2009) (open access) (arXiv:0810.4202).

Awards

11. The 24th Outstanding Paper Award of the Physical Society of Japan
(Publication 56, Theoretical Study on CaAgX)

10. The 20th Sir Martin Wood Prize

9. Journal of the Physical Society of Japan, Most Cited Articles in 2017 from Vol. 85 (2016)
(Publication 56 and 61, Experimental and theoretical studies on CaAgX)

8. The Akasaki Award, FY2014

7. The 17th Outstanding Paper Award of the Physical Society of Japan
(Publication 12, AOs2O6)

6. The 6th Young Scientist Award of the Physical Society of Japan (Division 3)
(vesignieite and Na4Ir3O8)

5. Physical Review B Editors' Suggestion
(Publicatoins 21: magnetization plateaus in volborthite and vesignieite, 50: neutron scattiering study of LiInCr4O8, 71: high-magnetic-field NMR of volborthite)

4. Journal of the Physical Society of Japan, Papers of Editors' Choice.
(Publications 8: vesignieite, 11: AOs2O6, 18: YMn2Zn20-xInx, 105: Ta2Pd3Te5 and Nb2Pd3Te5)

3. Poster Award, Presentations of Special Postdoctoral Researcher, FY2006, RIKEN.
(LiRh2O4)

2. Highly Frustrated Magnetism 2008, Best poster award.
(vesignieite)

1. 12th Young Scientist Presentation Award
(LixNayCo2O4)

Presentations (International)

40. Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
Yoshihiko Okamoto,
2024SNU-ISSP Workshop, Seoul, South Korea, May 24, 2024 (oral).

39. Large Magnetic-Field-Induced Strain in Cr-Based Magnets,
Yoshihiko Okamoto,
JKT-22, Kagoshima, Japan, Mar. 17th, 2024. (invited)

38. Superconductivity in Ternary Telluride Sc₆MTe₂ with 3d, 4d, and 5d Transition Metals,
Yoshihiko Okamoto,
MRM2023/IUMRS-ICA2023, Kyoto, Japan, December 12th, 2023. (invited)

37. 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)

36. 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 9th, 2023.(poster)

35. 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 28th, 2023. (poster)

34. 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, April 6th, 2023. (invited)

33. Large Magnetic-Field-Induced Strain in Geometrically Frustrated Sulfides,
Yoshihiko Okamoto, Tomoya Kanematsu, Masaki Mori, and Koshi Takenaka,
International Conference on Quantum Liquid Crystals 2021 (QLC2021), Online, Japan, May 13th, 2021. (oral)

32. Superconductivity in One-Dimensional Tellurides Nb2Pd3Te5 and Chemically-Doped Ta2Pd3Te5,
Yoshihiko Okamoto, Naoya Higashihara, Yuma Yoshikawa, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, and Koshi Takenaka,
International Conference on Quantum Liquid Crystals 2021 (QLC2021), Online, Japan, May 11th, 2021. (poster)

31. One-Dimensional Telluride Ta4SiTe4 as an Efficient Thermoelectric Material for Low-Temperature Applications,
Yoshihiko Okamoto,
14th Asia-Pacific Physics Conference 2019, Kuching, Malaysia, November 18th, 2019. (invited)

30. Equilateral-Triangular Trimer Formation in β-Pyrochlore Oxide CsW2O6,
Yoshihiko Okamoto, Rikuto Mitoka, Kenta Niki, Haruki Amano, Naoyuki Katayama, Hiroshi Sawa, Hisatomo Harima, and Koshi Takenaka,
International Conference on Strongly Correlated Electron Systems 2019, Okayama, Japan, September 24th, 2019. (oral)

29. Superconductivity in PtSbS with Noncentrosymmetric and Cubic Crystal Structure,
Yoshihiko Okamoto,
J-Physics 2019 International Conference & KINKEN-WAKATE 2019 Multipole Physics, Kobe, Japan,  September 19th, 2019. (invited)

28. Exploration of Novel Transition Metal Compounds Based on the Unique Crystal and Electronic Structures
Yoshihiko Okamoto
Research Frontier of Advanced Spectroscopies for Correlated Electron Systems, Sendai, Japan, June 13th, 2019. (invited)

27. A-Site Ordered Cr Spinel Sulfides: Alternating Antiferromagnetic and Ferromagnetic Interactions in the Breathing Pyrochlore Lattice,
Yoshihiko Okamoto
The 2nd Asia-Pacific Workshop on Quantum Magnetism, Bangalore, India, December 6th, 2018. (invited)

26. Calcium Silver Pnictide as a Candidate Nodal-Line Semimetal,
Yoshihiko Okamoto,
The 2nd TMS-PKU Alliance Workshop on Topological Materials and Quantum Materials, Beijing, China, September 25th, 2018. (invited)

25. Crystal Growth of 5d Transition Metal Compounds: β-Pyrochlore Oxide CsW2O6 and One-Dimensional Telluride Ta4SiTe4,
Yoshihiko Okamoto,
International Workshop on New Materials and Crystal Growth, Awaji, Hyogo, Japan, June 29th, 2018. (invited)

24. Superconductivity in the Noncentrosymmetric Iridium Phosphide ScIrP,
Yoshihiko Okamoto,
International Symposium on Superconductivity 2017, Tokyo, Japan, December 14th, 2017. (invited)

23. One-Dimensional Telluride Ta4SiTe4 as a High-Performance Thermoelectric Material,
Yoshihiko Okamoto, Taichi Wada, Yuma Yoshikawa, Takumi Inohara, Youichi Yamakawa, Ai Yamakage, and Koshi Takenaka,
The 6th Toyota RIKEN International Workshop 2017, Nagoya, Japan, November 11th, 2017. (oral)

22. Phase Transition in β-Pyrochlore Oxide CsW2O6,
Yoshihiko Okamoto, Haruki Amano, Kenta Niki, Rikuto Mitoka, Naoyuki Katayama, Hiroshi Sawa, Yuto Nakamura, Hideo Kishida, and Koshi Takenaka,
International Workshop on Multipole Physics and Related Phenomena, Hachimantai, Japan, September 28th, 2017. (oral)

21. High-Field Magnetization of Spin-3/2 Breathing Pyrochlore Antiferromagnets,
Yoshihiko Okamoto, Masaki Mori, Atsushi Miyake, Masashi Tokunaga, Akira Matsuo, Koichi Kindo, Zenji Hiroi, and Koshi Takenaka,
Highly Frustrated Magnetism 2016, Taipei, Taiwan, September 8th, 2016. (poster)

20. Superconductivity in the Noncentrosymmetric Iridium Phosphide ScIrP,
Yoshihiko Okamoto,
Dalian EMN Meeting, Dalian, China, July 27th, 2016. (invited)

19. Geometrical Frustration and Bond Alternation on the Breathing Pyrochlore Lattice,
Yoshihiko Okamoto,
OIST International Workshop on Novel Quantum Materials and Physics, Okinawa, Japan, May 15th, 2014. (invited)

18. Breathing Pyrochlore Lattice Realized in the A-Site Ordered Spinel Oxides LiGaCr4O8 and LiInCr4O8,
Yoshihiko Okamoto,
2014 APS March Meeting, Denver, United States, March 3rd, 2014. (invited)

17. Magnetic Properties of the Spin-1/2 Kagome Antiferromagnets: Vesignieite BaCu3V2O8(OH)2 and CdCu3(OH)6Br2,
Yoshihiko Okamoto, Makoto Yoshida, Hajime Ishikawa, Gøran J. Nilsen, Hiroyuki Yoshida, and Zenji Hiroi,
International Conference on Magnetism 2012, Busan, Korea, July 2012. (poster)

16. Structural and Magnetic Properties of Breathing Pyrochlore Lattice Antiferromagnets LiGaCr4O8 and LiInCr4O8,
Yoshihiko Okamoto, Gøran J. Nilsen, J. Paul Attfield, and Zenji Hiroi,
4th International Symposium on Structure-Property Relationship in Solid State Materials, Bordeaux, France, June 2012. (poster)

15. Magnetization Plateaus in Spin-1/2 Kagome Antiferromagnets: Volborthite and Vesignieite,
Yoshihiko Okamoto, Hiroyuki Yoshida, Masashi Tokunaga and Zenji Hiroi
International Conference on Frustration in Condensed Matter, Sendai, Japan, January 2011. (oral)

14. Heavy-Mass Fermi Liquid Realized in a Frustrated Itinerant-Electron Antiferromagnet "YMn2Zn20",
Yoshihiko Okamoto, Takeshi Shimizu, Jun-ichi Yamaura, Yoko Kiuchi and Zenji Hiroi
Highly Frustrated Magnetism 2010, Baltimore, United States, August 2010. (poster)

13. Discontinuous Lifshitz Transition Induced by Filling Control in NaxCoO2,
Yoshihiko Okamoto, Atsushi Nishio, Yoko Kiuchi and Zenji Hiroi
9th International Conference on Materials and Mechanisms on Superconductivity, Tokyo, Japan, September 2009. (poster)

12. Vesignieite BaCu3V2O8(OH)2 as a candidate spin-1/2 kagome antiferromagnet,
Yoshihiko Okamoto, Hiroyuki Yoshida and Zenji Hiroi
International Conference on Magnetism 2009, Karlsruhe, Germany, July 2009. (oral)

11. Thermoelectric Co and Rh oxides: NaxCoO2 and LiRh2O4,
Yoshihiko Okamoto,
Lorentz Center Workshop on Spin Caloritronics, Leiden, Netherlands, February 11th, 2009. (invited)

10. Synthesis and superconducting properties of iron oxyarsenide superconductors,
Yoshihiko Okamoto, Yuto Tsukamoto and Zenji Hiroi,
International Symposium on Anomalous Quantum Materials 2008, Tokyo, Japan, November 2008. (poster)

9. S = 1/2 kagome lattice in Cu2+-containing minerals,
Yoshihiko Okamoto, Hiroyuki Yoshida and Zenji Hiroi,
Highly Frustrated Magnetism 2008, Braunschweig, Germany, September 2008. (poster)
(Best Poster Award)

8. Precise control of the Na nonstoichiometry in NaxCoO2
Yoshihiko Okamoto, Atsushi Nishio, Daisuke Yoshizumi, Yoko Kiuchi, Masaki Ichihara and Zenji Hiroi,
2008 APS March Meeting, New Orleans, United States, March 2008. (oral)

7. New Ir and Rh oxides with spinel-related structures, Na4Ir3O8 and LiRh2O4,
Yoshihiko Okamoto, Seiji Niitaka, Ayako Yamamoto, Minoru Nohara, Masaya Uchida, Shinichi Shamoto, Hiroyuki Mitamura, Hiroko Aruga-Katori, Hiroshi Sawa, Akira Sekiyama, Shigetada Suga and Hidenori Takagi,
Kyoto Conference on Solid State Chemistry, Kyoto, Japan, November 2006. (poster)

6. Spin liquid state in Na4Ir3O8,
Yoshihiko Okamoto, Minoru Nohara and Hidenori Takagi,
Highly Frustrated Magnetism 2006, Itami, Japan, August 2006. (poster)

5. Spin liquid state in Na4Ir3O8,
Yoshihiko Okamoto, Minoru Nohara and Hidenori Takagi,
International Symposium on Anomalous Quantum Materials 2006, Okinawa, Japan, May 2006. (poster)

4. Layered rhodium oxide SrxRh2O4 as a thermoelectric material,
Yoshihiko Okamoto, Minoru Nohara and Hidenori Takagi,
The 5th Korea-Japan-Taiwan Symposium on Strongly Correlated Electron Systems, Busan, Korea, December 2004.(poster)

3. Na-ion ordering and charge disproportionation in Na0.3CoO2,
Yoshihiko Okamoto, Masaya Uchida, Minoru Nohara and Hidenori Takagi,
International Workshop on Novel Quantum Phenomena in Transition Metal Oxides, Sendai, Japan, November 2004.(poster)

2. Layered rhodium oxide SrxRh2O4 as a thermoelectric material,
Yoshihiko Okamoto, Minoru Nohara, and Hidenori Takagi,
IFCAM workshop on Electronic Properties of Cobalt Oxides, Sendai, Japan, June 2004.(oral)

1. Novel approach toward high-performance thermoelectric materials,
Yoshihiko Okamoto, Tomoko Eguchi, Fumiko Sakai, Minoru Nohara, Hidenori Takagi and Koichi Kitazawa,
CERC-ERATO 2002 International Workshop on "Phase Control of Correlated Electron System", Waikoloa, Hawaii, USA, May 2002. (poster)