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Development of superconducting density functional theory for conventional and unconventional superconductors

Research Project

Project/Area Number 19K14654
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
Research InstitutionThe University of Tokyo

Principal Investigator

Nomoto Takuya  東京大学, 大学院工学系研究科(工学部), 助教 (60804200)

Project Period (FY) 2019-04-01 – 2021-03-31
Project Status Completed (Fiscal Year 2020)
Budget Amount *help
¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords超伝導 / 第一原理計算 / 超伝導密度汎関数理論 / Migdal-Eliashberg理論 / 非従来型超伝導
Outline of Research at the Start

第一原理計算に基づく超伝導理論は, 現実の物質中で起きているスピン・軌道そして格子自由度が複雑に絡み合った多彩な物理を読み解き, その物性を予測するうえで必要不可欠な道具である. 本研究では特にスピン軌道相互作用の導入および電子格子相互作用機構の再考を軸に超伝導密度汎関数理論の改良を行い, 近年注目を集めるトポロジカル超伝導体や空間反転対称性の破れた超伝導体, また既存の手法で正しく転移温度を見積もれない従来型の超伝導体に適用し, その発現機構や超伝導状態の解明を試みる.

Outline of Final Research Achievements

In this project, we have developed a non-empirical method to calculate superconductivity. In particular, we have introduced the spin-orbit interaction into the superconducting density functional theory and implemented the odd-parity paring to analyze the mechanism of superconductivity in Sn1-xInxTe and CuxBi2Se3. We have also succeeded in quantitatively evaluating the transition temperature of superconductors with low transition temperatures. This has been achieved using the ab initio Migdal-Eliashberg calculation combining with the intermediate representation basis and the sparse sampling method.

Academic Significance and Societal Importance of the Research Achievements

超伝導密度汎関数理論へのスピン軌道相互作用の導入や奇パリティ超伝導計算の実装は、トポロジカル超伝導をはじめとする非従来型超伝導を第一原理的に計算する枠組みを提供する点で意義深い。また、本研究課題で、高精度な超伝導計算手法である第一原理Migdal-Eliashberg計算を転移温度の低い超伝導体に適用することが可能になった。これにより今まで超伝導密度汎関数理論では説明できなかった超伝導体の発現機構に、別手法からアプローチすることが可能となった。

Report

(3 results)
  • 2020 Annual Research Report   Final Research Report ( PDF )
  • 2019 Research-status Report
  • Research Products

    (4 results)

All 2020

All Journal Article (3 results) (of which Peer Reviewed: 3 results) Presentation (1 results) (of which Invited: 1 results)

  • [Journal Article] Microscopic characterization of the superconducting gap function in Sn1-xInxTe2020

    • Author(s)
      Nomoto T.、Kawamura M.、Koretsune T.、Arita R.、Machida T.、Hanaguri T.、Kriener M.、Taguchi Y.、Tokura Y.
    • Journal Title

      Physical Review B

      Volume: 101 Issue: 1 Pages: 014505-014505

    • DOI

      10.1103/physrevb.101.014505

    • Related Report
      2020 Annual Research Report 2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Efficient ab initio Migdal-Eliashberg calculation considering the retardation effect in phonon-mediated superconductors2020

    • Author(s)
      Tianchun Wang, Takuya Nomoto, Yusuke Nomura, Hiroshi Shinaoka, Junya Otsuki, T. Koretsune, and Ryotaro Arita
    • Journal Title

      Physical Review B

      Volume: 102 Issue: 13 Pages: 134503-134503

    • DOI

      10.1103/physrevb.102.134503

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Superconductivity in uniquely strained RuO2 films2020

    • Author(s)
      M. Uchida, T. Nomoto, M. Musashi, R. Arita, and M. Kawasaki
    • Journal Title

      Physical Review Letters

      Volume: 125 Issue: 14 Pages: 147001-147001

    • DOI

      10.1103/physrevlett.125.147001

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed
  • [Presentation] 第一原理Migdal-Eliashberg理論と遅延効果2020

    • Author(s)
      野本拓也
    • Organizer
      京都大学基礎物理学研究所研究会 「高温超伝導・非従来型超伝導研究の最前線:多様性と普遍性」
    • Related Report
      2020 Annual Research Report
    • Invited

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Published: 2019-04-18   Modified: 2022-01-27  

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