2021 Fiscal Year Final Research Report
Clarification of the relationship between unconventional superconductivity and antiferromagnetic quantum critical points by the measurement of the coefficient of volume thermal expansion
| Project/Area Number |
18K03508
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
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| Research Institution | University of Toyama |
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Principal Investigator |
TAYAMA Takashi 富山大学, 学術研究部理学系, 准教授 (20334344)
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Keywords | 異方的超伝導 / 量子臨界点 / 体膨張係数 / 体積磁歪係数 / DC磁化 / 置換効果 |
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| Outline of Final Research Achievements |
The thermal expansion coefficient and DC magnetization of Zn-substituted CeCoIn5 were precisely measured, and the temperature-pressure phase diagram in the negative pressure region was investigated. From the results, the position of the antiferromagnetic quantum critical point of CeCoIn5 under ambient pressure was determined, and the relationship between superconductivity and the antiferromagnetic quantum critical point was discussed. As a result, the possibility of the existence of two antiferromagnetic quantum critical points in CeCoIn5, one near zero field and the other near the upper critical field, is suggested. In other words, the antiferromagnetic quantum critical point near zero field is closely related to the mechanism of superconductivity, and the antiferromagnetic quantum critical point near the upper critical field may be closely related to the origin of the high-field superconducting phase, so-called Q phase.
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| Free Research Field |
物性物理学
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| Academic Significance and Societal Importance of the Research Achievements |
非従来型超伝導の発現機構はいまだ解明されておらず、固体物理学において最も重要な研究課題の一つとなっている。特に非従来型超伝導の量子臨界点の場所の特定は大きな課題となっているが、量子臨界点の場所は超伝導の発現によって隠れてしまうため正確な位置を特定するのが難しい。本研究はCeCoIn5の体膨張係数とDC磁化の精密測定により超伝導相内の短距離的な反強磁性相関を捉え、反強磁性量子臨界点の場所を探ったものである。この研究手法はCeCoIn5だけでなく他の強相関電子系の異方的超伝導体の研究にも用いることができることから、非従来型超伝導の研究全般に貢献できる可能性がある。
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