BCS-BEC crossover in multiband iron-based superconductors
Project/Area Number |
19H00649
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Research Category |
Grant-in-Aid for Scientific Research (A)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Medium-sized Section 13:Condensed matter physics and related fields
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Research Institution | The University of Tokyo |
Principal Investigator |
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Co-Investigator(Kenkyū-buntansha) |
水上 雄太 東京大学, 大学院新領域創成科学研究科, 助教 (80734095)
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Project Period (FY) |
2019-04-01 – 2023-03-31
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Project Status |
Completed (Fiscal Year 2022)
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Budget Amount *help |
¥46,540,000 (Direct Cost: ¥35,800,000、Indirect Cost: ¥10,740,000)
Fiscal Year 2021: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000)
Fiscal Year 2020: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000)
Fiscal Year 2019: ¥28,210,000 (Direct Cost: ¥21,700,000、Indirect Cost: ¥6,510,000)
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Keywords | 超伝導 / 電子構造 / ボーズ凝縮 / 電子ネマティック / 量子臨界点 / ボゴリューボフ準粒子 / 時間反転対称性 / マルチバンド / ネマティシティ / 弾性抵抗 / 上部臨界磁場 / 鉄系超伝導 / ギャップ構造 / 比熱 / 磁気トルク / 超伝導ギャップ / 磁場侵入長 / ミューオンスピン緩和 / 熱力学測定 / トンネル分光 |
Outline of Research at the Start |
BCS-BECクロスオーバーとは、電子が対を組んで超伝導になるときの電子対の引力の強さを変えた場合、転移温度がどのように変化するかなどを記述する、対状態の統一的理解に向けた物理的な枠組みである。今までは冷却原子系での研究が主流であったが、本研究では固体である鉄系超伝導体についてBCS-BECクロスオーバーの研究を行い、特に複数のバンドからなる電子構造を持つ場合の効果について調べ、転移温度の上限に関する新しい知見を得る。
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Outline of Final Research Achievements |
Systematic measurements of FeSe-based superconductors reveal the influence of the multiband electronic structure on the BCS-BEC crossover physics. The substitution of Se sites with isovalent S suppresses the electronic nematic order, and our experimental results show that a more BEC-like superconducting state is achieved as a result of the disappearance of the nematic order. This result cannot be explained by the ratio of the superconducting gap to the Fermi energy, as expected for single-band superconductivity, and suggests the existence of other important parameters in multiband superconductivity. In particular, the new viewpoint of the ratio of interband to intraband interactions is revealed to be important in the BCS-BEC crossover physics.
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Academic Significance and Societal Importance of the Research Achievements |
本研究は、今まで主に冷却原子系などに限られていたBCS-BECクロスオーバーの研究をより高い温度で実験可能な固体結晶の電子系において実現したものであり、さらに今まで全く考慮されていなかったマルチバンド電子構造の影響を初めて明らかにした点で学術的意義が高く、マルチバンドの電子状態におけるBCS-BECクロスオーバーという新しい研究領域の創出につながるものであると考えられる。特に、本研究により、今まで主に重要と考えられていた超伝導ギャップとフェルミエネルギーの比以外のパラメータの重要性を明らかにしたことで、超伝導のクロスオーバー相図や転移温度の上限に関する新しい指針を提示するものである。
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Report
(5 results)
Research Products
(75 results)
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[Journal Article] High-Pressure Phase Diagrams of FeSe1-xTex: Correlation between Suppressed Nematicity and Enhanced Superconductivity2021
Author(s)
K. Mukasa, K. Matsuura, M. Qiu, M. Saito, Y. Sugimura, K. Ishida, M. Otani, Y. Onishi, Y. Mizukami, K. Hashimoto, J. Gouchi, R. Kumai, Y. Uwatoko, and T. Shibauchi
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Journal Title
Nat. Commun.
Volume: 12
Issue: 1
Pages: 381-381
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Bond Directional Anapole Order in a Spin-Orbit Coupled Mott Insulator Sr2(Ir1-xRhx)O42021
Author(s)
H. Murayama, K. Ishida, R. Kurihara, T. Ono, Y. Sato, Y. Kasahara, H. Watanabe, Y. Yanase, G. Cao, Y. Mizukami, T. Shibauchi, Y. Matsuda, and S. Kasahara
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Journal Title
Phys. Rev. X
Volume: 11
Issue: 1
Pages: 011021-011021
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Dichotomy Between Orbital and Magnetic Nematic Instabilities in BaFe2S32020
Author(s)
S. Hosoi, T. Aoyama, K. Ishida, Y. Mizukami, K. Hashizume, S. Imaizumi, Y. Imai, K. Ohgushi, Y. Nambu, M. Kimata, S. Kimura, and T. Shibauchi
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Journal Title
Phys. Rev. Res.
Volume: 2
Issue: 4
Pages: 043293-043293
DOI
Related Report
Peer Reviewed / Open Access
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[Journal Article] Bose-Einstein Condensation Superconductivity Induced by Disappearance of the Nematic State2020
Author(s)
T. Hashimoto, Y. Ota, A. Tsuzuki, T. Nagashima, A. Fukushima, S. Kasahara, Y. Matsuda, K. Matsuura, Y. Mizukami, T. Shibauchi, S. Shin, and K. Okazaki
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Journal Title
Sci. Adv.
Volume: 6
Issue: 45
DOI
Related Report
Peer Reviewed / Open Access
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[Journal Article] Non-Fermi Liquid Transport in the Vicinity of the Nematic Quantum Critical Point of Superconducting FeSe1-xSx2020
Author(s)
W. K. Huang, S. Hosoi, M. Culo, S. Kasahara, Y. Sato, K. Matsuura, Y. Mizukami, M. Berben, N. E. Hussey, H. Kontani, T. Shibauchi, and Y. Matsuda
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Journal Title
Phys. Rev. Res.
Volume: 2
Issue: 3
Pages: 033367-033367
DOI
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Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Evidence for an FFLO State with Segmented Vortices in the BCS-BEC-Crossover Superconductor FeSe2020
Author(s)
S. Kasahara, Y. Sato, S. Licciardello, M. Culo, S. Arsenijevic, T. Ottenbros, T. Tominaga, J. Boker, I. Eremin, T. Shibauchi, J. Wosnitza, N. E. Hussey, and Y. Matsuda,
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Journal Title
Phys. Rev. Lett.
Volume: 124
Issue: 10
Pages: 107001-107001
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Journal Article] Novel Electronic Nematicity in Heavily Hole-Doped Iron Pnictide Superconductors2020
Author(s)
K. Ishida, M. Tsujii, S. Hosoi, Y. Mizukami, S. Ishida, A. Iyo, H. Eisaki, T. Wolf, K. Grube, H. v. Loehneysen, R. M. Fernandes, and T. Shibauchi,
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Journal Title
Proc. Natl. Acad. Sci. USA
Volume: 117
Issue: 12
Pages: 6424-6429
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Reciprocity between Local Moments and Collective Magnetic Excitations in the Phase Diagram of BaFe2(As1-xPx)22019
Author(s)
J. Pelliciari, K. Ishii, Y. Huang, M. Dantz, X. Lu, P. O. Velasco, V. N. Strocov, S. Kasahara, L. Xing, X. Wang, C. Jin, Y. Matsuda, T. Shibauchi, T. Das, and T. Schmitt,
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Journal Title
Commun. Phys.
Volume: 2
Issue: 1
Pages: 139-139
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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