2017 Fiscal Year Final Research Report
Exotic electronic state and quantum condensate in superconductors with ultra-shallow bands
| Project/Area Number |
15H03688
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Keywords | 非従来型超伝導 / ネマティック相 / 超シャロウバンド / BCS-BECクロスオーバー / 前駆電子対 / 超伝導揺らぎ / 超伝導ギャップ構造 / 軌道自由度 |
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| Outline of Final Research Achievements |
The superconducting semimetal FeSe has been found to be deep inside the BCS-BEC crossover regime. One of the significant achievements of this project is our successful growth of clean single crystals of FeSe1-xSx superconductors. Based on that, we have investigated their exotic electronic state and quantum condensate. In FeSe, experimental signatures of preformed Cooper pairing and emergence of a distinct field-induced superconducting phase with an unprecedented large spin imbalance have been discovered. In FeSe1-xSx superconductors, a novel type of quantum critical point (QCP) of pure nematic order without accompanying other orders is discovered. Moreover, a dramatic change in the superconducting gap structure is found across the nematic QCP of FeSe1-xSx. These fruitful findings obtained in this project provide pivotal information towards the understanding of exotic superconductors.
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| Free Research Field |
固体電子物性
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