2019 Fiscal Year Final Research Report
Origin of ferroelectric-like metal state in superconducting parent phase
Project/Area Number |
16K05434
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Condensed matter physics II
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Research Institution | Tokyo Institute of Technology |
Principal Investigator |
Yamaura Junichi 東京工業大学, 元素戦略研究センター, 特任准教授 (80292762)
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Project Period (FY) |
2016-04-01 – 2020-03-31
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Keywords | 鉄系超伝導 / 強誘電金属 / ネマチック状態 |
Outline of Final Research Achievements |
A hydrogen-substituted iron-based superconductor has a unique parent phase that loses spatial inversion symmetry and a superconducting phase adjacent to it. Since the superconducting phase is regarded as the fluctuations of superconductivity are ordered, the relationship between fluctuations in the ferroelectric metallic state and superconductivity is interesting. From the X-ray diffraction in LaFeAsO1-xHx, we found that the lattice symmetry lowering -nematic state- from a much higher temperature of the parent phase. From EXAFS measurement, we discovered that there is a local inversion symmetry breaking -ferroelectric fluctuation- from a much higher temperature region. This result suggests that the fluctuation of polar metal may be related to superconductivity.
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Free Research Field |
構造物性
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Academic Significance and Societal Importance of the Research Achievements |
本研究成果は、最近多くの超伝導体で観測されているネマチック状態が、水素置換系鉄系超伝導体でも存在していることを新たに証明し、さらに、超伝導体全体でも未知といえる、強誘電的金属状態の揺らぎと超伝導の関連を見出した重要な意義がある。また、反転対称を破った構造における超伝導は、上部臨界磁場の理論的限界値を上げる可能性があり、超伝導体の応用という面でも重要な情報を提供できると考えている。
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