2022 Fiscal Year Final Research Report
Research for topological superconductivity in compound devices of semiconductor and magnet
| Project/Area Number |
20H01835
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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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| Review Section |
Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
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| Research Institution | Fukuoka Institute of Technology (2022)
The University of Tokyo (2020-2021) |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | superconductivity / superconducting junction / semiconductor / topology |
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| Outline of Final Research Achievements |
We fabricated 1D proximity superconductor by depositing conventional superconducting wire on a ferromagnetic semiconductor (In,Fe)As. We measured the differential resistance as a bias current at low temperatures and observed resistance dip around zero-bias. This dip structure is robust against the external magnetic fields parallel to the wire. We expect that the dip structure corresponds to zero-bias conductance peaks which appears in topological superconducing junctions.
We also tried to control the electron spins via quantum Hall edge states by changing the inter-channel transition probability with the potential modulation.
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| Free Research Field |
Physics
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| Academic Significance and Societal Importance of the Research Achievements |
本研究はこれまで外部磁場が必要であった近接効果による一次元トポロジカル超伝導体を，強磁性半導体を用いてゼロ磁場で創り出することを試み，トポロジカル超伝導の存在を示すと思われる兆候を観測した．これがトポロジカル超伝導によるものであれば強磁性半導体の磁性を電場によってコントロールすることで，完全にゼロ磁場で，制御可能なトポロジカル超伝導接合が実現できることになり，比較的複雑な構造のトポロジカル量子計算素子の実現も期待できる．また，強磁性半導体は有力なスピントロニクス材料であるが，同時に量子計算への応用可能性も大きいと示すことができた．
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