2018 Fiscal Year Final Research Report
Search for topological phase transition induced by broken inversion symmetry
| Project/Area Number |
17K18753
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Condensed matter physics and related fields
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Research Collaborator |
Naritsuka Masahiro
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| Project Period (FY) |
2017-06-30 – 2019-03-31
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| Keywords | トポロジカル物性 / 超伝導 |
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| Outline of Final Research Achievements |
We have fabricated artificial superlattices using heavy-fermion superconductors to control topological phase transition and to create exotic superconducting state by artificially introducing broken inversion symmetry. In CeCoIn5/YbCoIn5/YbRhIn5 tricolor superlattice, global inversion symmetry breaking is artificially introduced in two-dimensional heavy fermion superconductors. We found an anomalous enhancement of the upper critical field at low temperature, suggesting the appearance of a new high-field superconducting phase, which has been theoretically predicted in superconductors without inversion symmetry. In superlattices comprised of heavy-fermion superconductor CeCoIn5 and antiferromagnet CeRhIn5, pairing interaction is largely enhanced by injecting the antiferromagnetic fluctuations into superconducting layer from adjacent antiferromagnetic layer through the interfaces.
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| Free Research Field |
低温物理
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| Academic Significance and Societal Importance of the Research Achievements |
空間反転対称性の破れの人工導入や界面を通じた反強磁性揺らぎの注入により、超伝導状態を大きく制御できることが明らかとなった。特に前者ではトポロジカル超伝導の発現が理論的に指摘されているが、通常の物質では空間反転対称性の破れは結晶構造によって決定されてしまうため、空間反転対称性の破れを制御することが困難な状況であり、物質探索に依存していた状況であった。これに対し、人工超格子を用いた手法は連続制御が可能であり、トポロジカル超伝導の新しい探索手法を提示するものである。
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