2022 Fiscal Year Final Research Report
Giant thermoelectric response and thermoelectric functions in one-dimensional Dirac electron materials
Project/Area Number |
20H02603
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 29010:Applied physical properties-related
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Research Institution | The University of Tokyo (2022) Nagoya University (2020-2021) |
Principal Investigator |
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Co-Investigator(Kenkyū-buntansha) |
山川 洋一 名古屋大学, 理学研究科, 講師 (60750312)
山影 相 名古屋大学, 理学研究科, 講師 (90750290)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 熱電変換 / ディラック電子 / 低次元電子系 / 新材料開拓 |
Outline of Final Research Achievements |
We aimed to develop high-performance thermoelectric materials by utilizing giant thermoelectric response of Ta4SiTe4, which is a one-dimensional Dirac electron system. Reflectance measurements on the single crystals indicated the presence of a narrow gap of approximately 0.1 eV and moderately strong anisotropy, which is related to the high thermoelectric performance in this system. We also succeeded in synthesizing solid solutions between Ta4SiTe4 and Nb4SiTe4, which is necessary for practical materials. We developed new materials that are expected to have similar electronic state to Ta4SiTe4, and found that Ti-substituted Ta2Ni3Te5 exhibited a large Seebeck coefficient of 125 microV K-1 at room temperature, which is considerably high for a metallic material.
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Free Research Field |
固体化学、物性物理学
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Academic Significance and Societal Importance of the Research Achievements |
本研究においてTa4SiTe4の太さ数100 μmの単結晶が初めて得られたことにより、本物質の反射率やホール抵抗を初めて測定することができた。これにより本物質系において「穏やかな一次元性をもつディラック電子系」の電子状態が巨大な熱電応答をもたらしていることを実験的に示せた。これは新たな低温用材料設計指針であり、熱電変換の分野にとって意義をもつ。実際本研究では、この指針に従って物質探索を行うことにより、有望な新材料候補Ta2Ni3Te5を見出した。今後、化学組成の制御により大幅な性能向上が期待される。
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