2014 Fiscal Year Final Research Report
Phase structures of superconducting gaps in iron-based superconductors
| Project/Area Number |
24340089
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Partial Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | The Institute of Physical and Chemical Research |
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Principal Investigator |
HANAGURI Tetsuo 独立行政法人理化学研究所, 創発物性科学研究センター, チームリーダー (40251326)
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| Co-Investigator(Renkei-kenkyūsha) |
NIITAKA Seiji 独立行政法人理化学研究所, 無機電子複雑系研究チーム, 基幹研究所研究員 (60392057)
KITAGAWA Kentaro 東京大学, 物性研究所, 特任研究員 (90567661)
SASAGAWA Takao 東京工業大学, 応用セラミックス研究所, 准教授 (30332597)
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| Research Collaborator |
KIM KeeHoon
WATASHIGE Tatsuya
KASAHARA Shigeru
SHIBAUCHI Takasada
MATSUDA Yuji
WOFT Thomas
MEINGAST Christoph
V. LÖHNEYSEN Hilbert
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Keywords | 鉄系超伝導体 / 走査型トンネル顕微鏡 / 超伝導ギャップ / 準粒子干渉効果 / BCS-BECクロスオーバー |
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| Outline of Final Research Achievements |
We have used spectroscopic imaging scanning tunneling microscopy to investigate the superconducting gaps and the electronic states of the iron-based superconductors LiFeAs and FeSe. We found that some defects in LiFeAs generate in-gap bound state. We also examined the effects of twin boundaries on the superconducting gap of FeSe and found that the twin boundary induces a novel superconducting state that breaks the time-reversal symmetry. The band dispersions of FeSe were determined by the quasi-particle interference effect. The estimated Fermi energy is smaller than 10 meV, being of the same order as the superconducting gap. This means that FeSe is in the BCS-BEC crossover regime. The observed quasi-particle interference patterns possess strong in-plane anisotropy which may reflect the orbital ordering in this material.
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| Free Research Field |
低温物性
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