Publications
2024 and Papers in press
[54] Okuda, Y., Hirose, K., Ohta, K., Kawaguchi-Imada, S., & Oka, K. Electrical conductivity of dense MgSiO3 melt under static compression. Geophysical Research Letters. 51, e2024GL109741. https://doi.org/10.1029/ 2024GL109741
[53] Kawaguchi-Imada, S., Sinmyo, R., Ohta, K., Kawaguchi, S., & Kobayashi, T. Submillisecond in situ X-ray diffraction measurement system with changing temperature and pressure using diamond anvil cells at beamline BL10XU/SPring-8. Journal of Synchrotron Radiation. 31, 343–354.
2023
[52] Ohta, K., Suehiro, S., Kawaguchi, S., Okuda, Y., Wakamatsu, T., Hirose, K., Ohishi, Y., Kodama, M., Hirai, S., & Azuma, S. Measuring the electrical resistivity of liquid iron to 1.4 Mbar. Physical Review Letters, 130, 266301.
[51] Nagaya, Y., Gomi, H., Ohta, K., & Hirose, K. Equations of state for B2 and bcc Fe1-xSix. Physics of the Earth and Planetary Interirors, 341, 107046.
[50] Ohta, K. Ammonia and the ice giants. Nature Physics, https://doi.org/10.1038/s41567-023-02081-9.
[49] Park, Y., Yonemitsu, K., Hirose, K., Kuwayama, Y., Azuma, S., & Ohta, K. Viscosity of Earth's inner core constrained by Fe-Ni interdiffusion in Fe-Si alloy in an internal-resistive-heated diamond anvil cell. American Mineralogist, 108, 1064–1071.
[48] Okuda, Y. & Ohta, K. Heat flow from the Earth's core inferred from experimentally determined thermal conductivity of the deep lower mantle. Core-manltle Co-evolution: An interdisciplinary Approarch AGU monograph, 133–144.
[47] Hasegawa, A., Ohta, K., Yagi, T., & Hirose, K. Thermal conductivity of platinum and periclase under extreme conditions of pressure and temperature. High Pressure Research, https://doi.org/10.1080/08957959.2023.2193892.
2022
[46] Okuda, Y., Oka, K., Kubota, Y., Inada, M., Kurita, N., Ohta, K., & Hirose, K. High P–T impedance measurements using a laser-heated diamond anvil cell. Review of Scientific Instruments, 93, 105103. https://doi.org/10.1063/5.0097883
[45] Wakamatsu, T., Ohta, K., Tagawa, S., Yagi, T., Hirose, K., & Ohishi, Y. Compressional wave velocity for iron hydrides to 100 gigapascals via picosecond acoustics. Physics and Chemistry of Minerals, 49, 17. https://doi.org/10.1007/s00269-022-01192-8
[44] Aoyama, T., Ohta, K., Shimizu, K., & Ohgushi, K. Persistent spin-orbit Mott insulating state in highly compressed post-perovskite CaIrO3. Journal of the Physical Society of Japan, 91, 045003. https://doi.org/10.7566/JPSJ.91.045003
2021
[43] Zhang, Z., Zhang, D. -B., Onga, K., Hasegawa, A., Ohta, K., Hirose, K., & Wentzcovitch, R. Thermal conductivity of CaSiO3 perovskite. Physical Review B, 104, 184101. https://doi.org/10.1103/PhysRevB.104.184101
[42] Sakuraba, H., Kurokawa, Y., Genda, H., & Ohta, K. Numerous chondritic impactors and oxdized magma ocean set Earth's volatile depletion. Scietific Reports, 11, 20894. https://doi.org/10.1038/s41598-021-99240-w
[41] Okuda, Y., Ohta, K., Nishihara, Y., Hirao, N., Wakamatsu, T., Suehiro, S., Kawaguchi, I. S., & Ohishi, Y. Low-spin ferric iron in primordial bridgmanite crystallized from a deep magma ocean. Scientific Reports, 11, 19471. https://doi.org/10.1038/s41598-021-98991-w
[40] Ohta, K., & Hirose, K. The thermal conductivity of the Earth's core and implications for its therma and compositional evolution. National Science Review, 8, nwaa303. https://doi.org/10.1093/nsr/nwaa303
[39] Okuda, Y., Kimura, S., Ohta, K., Park, Y., Wakamatsu, T., Mashino, I., & Hirose, K. A cylindrical SiC heater for an externally heated diamond anvil cell to 1500 K. Review of Scientific Instruments, 92, 015119. https://doi.org/10.1063/5.0036551
2020
[38] Ohta, K., Wakamatsu, T., Kodama, M., Kawamura, K., & Hirai, S. Laboratory-based X-ray computed tomography for 3D imaging of samples in a diamond anvil cell in situ at high pressures. Review of Scientific Instruments, 91, 093703 (2020). https://doi.org/10.1063/5.0014486
[37] Okuda, Y., Ohta, K., Sinmyo, R., Hirose, K., & Ohishi, Y. Anomarous compressibility in (Fe,Al)-bearing bridgmanite: implications for the spin state of iron. Physics and Chemistry of Minerals, 47, 40 (2020). https://doi.org/10.1007/s00269-020-01109-3
[36] Okuda, Y., Ohta, K., Hasegawa, A., Yagi, T., Hirose, K., Kawaguchi, S. I., & Ohishi, Y. Thermal conductivity of Fe-bearing post-perovskite in the Earth's lowermost mantle. Earth and Planetary Science Letters, 547, 116466 (2020). https://doi.org/10.1016/j.epsl.2020.116466
[35] Inoue, H., Suehiro, S., Ohta, K., Hirose, K., & Ohishi, Y. Resistivity saturation of hcp Fe-Si alloys in an internally heated diamond anvil cell: A key to assessing the Earth's core conductivity. Earth and Planetary Science Letters 543, 116357 (2020). https://doi.org/10.1016/j.epsl.2020.116357
[34] Kato, C., Umemoto, K., Ohta, K., Tagawa, S., Hirose, K., & Ohishi, Y. Stability of fcc phase FeH to 137 GPa. American Mineralogist 105, 917-921 (2020). DOI: https://doi.org/10.2138/am-2020-7153
2019
[33] Suehiro, S., Wakamatsu, T., Ohta, K., Hirose, K., & Ohishi, Y. High-temperature electrical resistivity measurements of hcp iron to Mbar pressure in an internally resistive heated diamond anvil cell. High Pressure Research 39, 579-587 (2019). https://doi.org/10.1080/08957959.2019.1692008
[32] Matsuoka, T., Muraoka, S., Ishikawa, T., Niwa, K., Ohta, K., Hirao, N., Kawaguchi, S., Ohishi, Y., Shimizu, K., & Sasaki, S. Hydrogen-storing salt NaCl(H2) synthesized at high pressure and high temperature. The Journal of Physical Chemistry C 123, 25074-25080 (2019). https://doi.org/10.1021/acs.jpcc.9b06639
[31] Hasegawa, A., Yagi, T., & Ohta, K. Combination of pulsed light heating thermoreflectance and laser-heated diamond anvil cell for in-situ pressure-temperature thermal diffusivity measurements. Review of Scientific Instrum 90, 074901 (2019). https://doi.org/10.1063/1.5093343
[30] Okuda, Y., Ohta, K., Sinmyo, R., Hirose, K., Yagi, T, & Ohishi, Y. Effect of spin transition of iron on the thermal conductivity of (Fe,Al)-bearing bridgmanite. Earth and Planetary Science Letters 520, 188-198 (2019). https://doi.org/10.1016/j.epsl.2019.05.042
[29] Hasegawa, A., Ohta, K., Yagi, T., Hirose, K., Okuda, Y., & Kondo, T. Composition and pressure dependence of lattice thermal conductivity of (Mg,Fe)O solid solutions. Comptes Rendus Geoscience 351, 229-235 (2019). https://doi.org/10.1016/j.crte.2018.10.005
[28] Ohta, K., Suehiro, S., Hirose, K., & Ohishi, Y. Electrical resistivity of fcc phase iron hydrides at high pressures and temperatures. Comptes Rendus Geoscience 351, 147-153 (2019). https://doi.org/10.1016/j.crte.2018.05.004
2018
[27] Ohta, K., Nishihara, Y., Sato, Y., Hirose, K., Yagi, T., Kawaguchi, S., Hirao, N., & Ohishi Y. An experimental examinaion of thermal conductivity anisotropy in hcp iron. Frontiers in Earth Science 6, 176 (2018). https://doi.org/10.3389/feart.2018.00176
[26] Wakamatsu, T., Ohta, K., Yagi, T., Hirose, K., & Ohishi, Y. Measurements of sound velocity in iron-nickel alloys by femtosecond laser pulses in a diamond anvil cell. Physics and Chemistry of Minerals 45, 589-595, (2018). https://doi.org/10.1007/s00269-018-0944-3
2017
[25] Suehiro, S., Ohta, K., Hirose, K., Morard, G., & Ohishi Y. The influence of sulfur on the electrical resistivity of hcp iron: implications for the core conductivity of Mars and Earth. Geophysical Research Letters 44, 8254-8259 (2017). https://doi.org/10.1002/2017GL074021
[24] Matsuoka, T., Kuno, K., Ohta, K., Sakata, M., Nakamoto, Y., Hirao, N., Ohishi, Y., Shimizu, K., Kume, T., & Sasaki, S. Lithium polyhydrides synthesized under high pressure and high temperature. Journal of Raman Spectroscopy 48, 1222-1228 (2017). https://doi.org/10.1002/jrs.5183
[23] Okuda, Y., Ohta, K., Yagi, T., Sinmyo, R., Wakamatsu, T., Hirose, K., & Ohishi, Y. The effect of iron and aluminum incorporation on lattice thermal conductivity of bridgmanite at the Earth's lower mantle. Earth and Planetary Science Letters 474, 25-31 (2017). https://doi.org/10.1016/j.epsl.2017.06.022
[22] Ohta, K., Yagi, T., Hirose, K., & Ohishi, Y. Thermal conducitivity of ferropericlase in the Earth's lower mantle. Earth and Planetary Science Letters 465, 29-37 (2017). https://doi.org/10.1016/j.epsl.2017.02.030
2016
[21] Ohta, K., Kuwayama, Y., Hirose, K., Shimizu, K., & Ohishi, Y. Experimental determination of the electrical resistivity of iron at Earth's core conditions. Nature 534, 95-98 (2016). https://doi.org/10.1038/nature17957
[20] Tagawa, S., Ohta, K., Hirose, K., Kato, C., & Ohishi, Y. Compression of Fe-Si-H alloys to core pressures. Geophysical Research Letters 43, 3686-3692 (2016). https://doi.org/10.1002/2016GL068848
2015
[19] Ohta, K., Ichimaru, K., Einaga, M., Kawaguchi, S., Shimizu, K., Matsuoka, T., Hirao, N., & Ohishi, Y. Phase boundary of hot dense fluid hydrogen. Scientific Reports 5, 16560 (2015). https://doi.org/10.1038/srep16560
[18] Kuno, K., Matsuoka, T., Nakagawa, T., Hirao, N., Ohishi, Y., Shimizu, K., Takahama, K., Ohta, K., Sakata, M., Nakamoto, Y., Kume, T., & Sasaki, S. Heating of Li in hydrogen: Possible synthesis of LiHx. High Pressure Research 35, 16-21 (2015). https://doi.org/10.1080/08957959.2014.999677
2014
[17] Imada, S., Ohta, K., Yagi, T., Hirose, K., Yoshida, H., & Nagahara, H. Measurements of lattice thermal conductivity of MgO to core-mantle boundary pressures. Geophysical Research Letters 41, 4542-4547 (2014). https://doi.org/10.1002/2014GL060423
[16] Ohta, K., Fujino, K., Kuwayama, Y., Kondo, T., Shimizu, K., & Ohishi, Y. Highly conductive iron-rich (Mg,Fe)O magnesiowustite and its stability in the Earth's lower mantle. Journal of Geophysical Research Solid Earth 119, 4656-4665 (2014). https://doi.org/10.1002/2014JB010972
[15] Matsuoka, T., Sakata, M., Nakamoto, Y., Takahama, K., Ichimaru, K., Mukai, K., Ohta, K., Hirao, N., Ohishi, Y., & Shimizu, K. Pressure-induced re-entrant of metallic phase of lithium. Physical Review B 89, 144103 (2014). https://doi.org/10.1103/PhysRevB.89.144103
[14] Ohta, K., Yagi, T., & Hirose, K. Thermal diffusivities of MgSiO3 and Al-bearing MgSiO3 perovskites. American Mineralogist 99, 94-97 (2014). http://dx.doi.org/10.2138/am.2014.4598
2013
[13] Gomi, H., Ohta, K., Hirose, K., Labrosse, S., Caracas, R., Verstraete, M. J., & Hernlund, J. The high conductivity of iron and thermal evolution of the Earth's core. Physics of the Earth and Planetary Interiors 224, 88-103 (2013). https://doi.org/10.1016/j.pepi.2013.07.010
2012
[12] Sugimura, E., Komabayashi, T., Ohta, K., Hirose, K., Ohishi, Y., & Dubrovinsky, L. Experimental evidence of superionic conduction in H2O ice. Journal of Chemical Physics 137, 194505 (2012). https://doi.org/10.1063/1.4766816
[11] Ohta, K., Yagi, T., Taketoshi, N., Hirose, K., Komabayshi, T., Baba, T., Ohishi, Y., & Hernlund, J. Lattice thermal conductivity of MgSiO3 perovskite and post-perovskite at the core-mantle boundary. Earth and Planetary Science Letters 349-350, 109-115 (2012). https://doi.org/10.1016/j.epsl.2012.06.043
[10] Ohta, K., Cohen, R. E., Hirose, K., Haule, K., Shimizu, K., & Ohishi, Y. Experimental and theoretical evidence for pressure-induced metallization in FeO with the rock-salt type structure. Physical Review Letters 108, 026403 (2012). https://doi.org/10.1103/PhysRevLett.108.026403
2011
[9] Ozawa, H., Hirose, K., Ohta, K., Ishii, H., Hiaoka, N., Ohishi, Y., & Seto, Y, Spin crossover, structural change, and metallization in NiAs-type FeO at high pressure. Physical Review B 84, 134417 (2011). https://doi.org/10.1103/PhysRevB.84.134417
[8] Yagi, T., Ohta, K., Kobayashi, K., Taketoshi, N., Hirose, K., & Baba, T. Thermal diffusivity measurement in diamond anvil cell using light pulse thermoreflectance technique. Measurement Science and Technology 22, 024011 (2011). https://doi.org/10.1088/0957-0233/22/2/024011
2010
[7] Iizuka, T., McCulloch, M.T., Komiya, T., Shibuya, T., Ohta, K., Ozawa, H., Sugimura, E., & Collerson, K.D. Monazite geochronology and geochemistry of meta-sediments in the Narryer Gneiss Complex, Western Australia: constraints on the tectonothermal history and provenance. Contributions to Mineralogy and Petrology 160, 803-823 (2010). https://doi.org/10.1007/s00410-010-0508-0
[6] Ohta, K., Hirose, K., Shimizu, K., & Ohishi, Y. High-pressure experimental evidence for metal FeO with normal NiAs-type structure. Physical Review B 82, 174120 (2010). https://doi.org/10.1103/PhysRevB.82.174120
[5] Ohta, K., Hirose, K., Shimizu, K., Sata, N., & Ohishi, Y. The electrical resistance measurements of (Mg,Fe)SiO3 perovskite at high pressures and implications for electronic spin transition of iron. Physics of the Earth and Planetary Interiors 180, 154-158 (2010). https://doi.org/10.1016/j.pepi.2009.11.002
[4] Ohta, K., Hirose, K., Ichiki, M., Shimizu, K., Sata, N., & Ohishi, Y. Electrical conductivities of pyrolitic mantle and MORB materials up to the lowermost mantle conditions. Earth and Planetary Science Letters 289, 497-502 (2010). https://doi.org/10.1016/j.epsl.2009.11.042
2008
[3] Ohta, K., Onoda, S., Hirose, K., Sinmyo, R., Shimizu, K., Sata, N., Ohishi, Y., & Yasuhara, A. The electrical conductivity of post-perovskite in Earth’s D” layer. Science 320, 89-91 (2008). DOI: 10.1126/science.1155148
[2] Ohta, K., Hirose, K., Lay, T., Sata, N., & Ohishi, Y. Phase transitions in pyrolite and MORB at lowermost mantle conditions: Implications for a MORB-rich pile above the core-mantle boundary. Earth and Planetary Science Letters 267, 107-117 (2008). https://doi.org/10.1016/j.epsl.2007.11.037
2007
[1] Ohta, K., Hirose, K., Onoda, S., & Shimizu, K. The effect of iron spin transition on electrical conductivity of (Mg,Fe)O magnesiowüstite. Proceedings of the Japan Academy Ser. B 83, 97-100 (2007). https://doi.org/10.2183/pjab.83.97
Proceedings and articles written in Japanese
太田 健二, 高圧力下における地球深部物質の電気・熱伝導率測定, 高圧力の科学と技術 26, 189-195 (2016). https://doi.org/10.4131/jshpreview.26.189
松岡岳洋、坂田雅文、太田健二、中本有紀、平尾直久、大石泰生、清水克哉, 超高圧下でのX線回折・電気抵抗の同時測定による、Liの金属-絶縁体-金属リエントラント相転移の発見, 放射光 28, 49-55 (2015).
太田 健二, 八木 貴志, 廣瀬 敬, パルス光加熱サーモリフレクタンス法を用いた高圧力下での下部マントル鉱物の格子熱伝導率測定, 高圧力の科学と技術 24, 118-125 (2014). https://doi.org/10.4131/jshpreview.24.118
太田 健二, 廣瀬 敬, 新名 良介, 小野田 朱々江, 清水 克哉, レーザー加熱式ダイヤモンドセルを用いた (Mg,Fe)SiO3ポストペロフスカイト相の電気伝導度測定, 高圧力の科学と技術 18, 260-266 (2008). https://doi.org/10.4131/jshpreview.18.260