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Control of spin and polarization by hidden topological singularities

Research Project

Project/Area Number 20K14390
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
Research InstitutionThe University of Tokyo (2021-2022)
Institute of Physical and Chemical Research (2020)

Principal Investigator

Hirayama Motoaki  東京大学, 大学院工学系研究科(工学部), 特任准教授 (70761005)

Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2021: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2020: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Keywordsトポロジカル相 / 物質探索 / 第一原理計算 / 電子構造 / Weyl半金属 / 電子化物 / データベース
Outline of Research at the Start

本申請では、バンド交叉以外の隠れた幾何学的状態の学理構築と材料提案を通し、物質の新たな量子制御の可能性を開拓する。本研究では、まずモデルケースを用いて、新しいタイプの幾何学的状態の特徴付けを行う。得られた知見を元に、対称性の観点から物質を探索し、第一原理手法によって具体的なトポロジカル物質の提案を行う。電子の波動関数に内在する見えない特異構造を探索し、その制御を通して物質にどのような機能を付与するかを、本研究で明らかにする。

Outline of Final Research Achievements

In this study, we search novel topological materials and their physical properties, such as topological insulating phases that cannot be determined from the shape of the band structure. In the first year, we proposed an electride of apatite as a realistic material for three-dimensional higher-order topological crystal insulating phases with quantized charge at the hinge. We also classified topological electrides and proposed new materials. In the next year, we investigated a systematic material design method for topological electrides using the database, and were able to discover new topological electrides such as LaC. In the final year, we succeeded in finding several relativistic topological molecular crystals such as K4Ba2[SnBi4].

Academic Significance and Societal Importance of the Research Achievements

本研究では、アパタイトや分子性結晶といった、従来の物性物理分野とは異なる物質系において新たなトポロジカル物性を見出しており、材料科学・化学分野との分野横断型の研究が期待される。また、Na3Biなどの既存のトポロジカル相の代表物質が電子化物であったことを発見しており、当該物質における非自明な物性と、電子化物としての性質の関係は今後興味が持たれるところである。また、我々が考案した既存の物質から系統的に新たなトポロジカル電子化物を予言する方法論は、第一原理計算とビックデータを活用しており、電子化物の設計指針として汎用性が高い。

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (8 results)

All 2022 2021 2020

All Journal Article (5 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 5 results,  Open Access: 3 results) Presentation (3 results) (of which Int'l Joint Research: 1 results,  Invited: 3 results)

  • [Journal Article] Interstitial‐Electron‐Induced Topological Molecular Crystals2022

    • Author(s)
      Yu Tonghua、Arita Ryotaro、Hirayama Motoaki
    • Journal Title

      Advanced Physics Research

      Volume: 2 Issue: 3 Pages: 2200041-2200041

    • DOI

      10.1002/apxr.202200041

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] First-principles design of halide-reduced electrides: Magnetism and topological phases2021

    • Author(s)
      Yu Tonghua、Hirayama Motoaki、Flores-Livas Jos? A.、Huebsch Marie-Therese、Nomoto Takuya、Arita Ryotaro
    • Journal Title

      Physical Review Materials

      Volume: 5 Issue: 4 Pages: 044203-044203

    • DOI

      10.1103/physrevmaterials.5.044203

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Higher-order topological crystalline insulating phase and quantized hinge charge in topological electride apatite2020

    • Author(s)
      Hirayama Motoaki、Takahashi Ryo、Matsuishi Satoru、Hosono Hideo、Murakami Shuichi
    • Journal Title

      Physical Review Research

      Volume: 2 Issue: 4 Pages: 043131-043131

    • DOI

      10.1103/physrevresearch.2.043131

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Enhancement of the transverse thermoelectric conductivity originating from stationary points in nodal lines2020

    • Author(s)
      Minami Susumu、Ishii Fumiyuki、Hirayama Motoaki、Nomoto Takuya、Koretsune Takashi、Arita Ryotaro
    • Journal Title

      Physical Review B

      Volume: 102 Issue: 20 Pages: 205128-205128

    • DOI

      10.1103/physrevb.102.205128

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Magnetic exchange coupling in cuprate-analog d9 nickelates2020

    • Author(s)
      Nomura Yusuke、Nomoto Takuya、Hirayama Motoaki、Arita Ryotaro
    • Journal Title

      Physical Review Research

      Volume: 2 Issue: 4 Pages: 043144-043144

    • DOI

      10.1103/physrevresearch.2.043144

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] Ab initio material design of strongly correlated and topological systems utilizing covalent bonding2022

    • Author(s)
      Motoaki Hirayama
    • Organizer
      MRM 2022
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] 空隙電子によるバンド反転設計と分子性結晶への応用2022

    • Author(s)
      平山元昭
    • Organizer
      分子性固体オンラインセミナー
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] 空隙軌道による相対論的トポロジカル分子性結晶2022

    • Author(s)
      平山元昭
    • Organizer
      高密度共役の科学 第3回オンラインセミナー
    • Related Report
      2022 Annual Research Report
    • Invited

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Published: 2020-04-28   Modified: 2024-01-30  

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