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Elucidation of the origin of Anderson localization and exploration of superconductivity by controlling it in electron-correlated oxides

Research Project

Project/Area Number 20H02704
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Review Section Basic Section 32020:Functional solid state chemistry-related
Research InstitutionTokyo Metropolitan University (2022-2023)
Tohoku University (2020-2021)

Principal Investigator

Oka Daichi  東京都立大学, 理学研究科, 准教授 (20756514)

Project Period (FY) 2020-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000)
Fiscal Year 2023: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2022: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2021: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2020: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
Keywordsアンダーソン局在 / 金属絶縁体転移 / 酸化物 / 酸窒化物 / エピタキシー / 複合アニオン / 超伝導 / 電子相関 / 二核錯体
Outline of Research at the Start

高温超電導体開発の指針に電子相関の導入があり、これまでモット絶縁体の相転移現象が盛んに研究されてきた。一方、超伝導体相とアンダーソン絶縁体相が隣接する例も存在する。このような系で局在を抑制できれば新たな超伝導体探索の指針になり得る。本研究では局在を決定づけるパラメータとして、理論で検討されてきた不規則性・次元性に加えて、軌道分布に着目する。導電性酸化物を対象に、金属・絶縁体相図を実験的に作成する。得られた相図から局在による絶縁化を抑制するための指針を見出し、超伝導体をはじめとする機能性材料の開発を行う。くわえて、発見した超伝導体を用いたエピタキシャル接合素子の作成にも取り組む。

Outline of Final Research Achievements

We investigated the factors inducing the metal-insulator transition due to electron localization in electron-correlated conductive oxides, such as Nb-based oxides and oxynitrides, V-based layered oxides, Ru oxides, and rare-earth monoxides. As a result, we found that the disorder of the anion arrangement can be more significant than the Coulomb interaction between electrons, and that the dimensionality-induced metal-insulator transition appears by reducing the conductive layer or film thickness, but at the same time, the emergence of weak localization is determined by the interlayer interaction. We also found that the expansion of the orbital distribution leads to improved electrical conductivity. In rare-earth monoxides, the mobility of the itinerant 5d electrons changes depending on the number of the localized 4f electrons, and superconducting heterostructures were successfully fabricated.

Academic Significance and Societal Importance of the Research Achievements

本研究では電子相関系酸化物においてアニオン配列、層構造、格子歪み、膜厚、軌道分布の大きさといった要素が電子局在を引き起こす具体的な条件を実験的に検証することができ、これらのパラメータの制御方法が開発された。また、本研究では多様な酸化物を高品質なエピタキシャル薄膜として合成するための合成手法開発という面でも多様な手法を見出すことができ、理論的に高温超伝導を発現すると期待される層状酸化物のエピタキシャル合成も可能となった。これらの知見や技術は、今後、超伝導体をはじめとする導電性材料の開発に活用できると期待される。

Report

(5 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Annual Research Report
  • 2021 Annual Research Report
  • 2020 Annual Research Report
  • Research Products

    (24 results)

All 2024 2023 2022 2021 2020 Other

All Journal Article (8 results) (of which Peer Reviewed: 8 results,  Open Access: 1 results) Presentation (15 results) (of which Int'l Joint Research: 1 results) Remarks (1 results)

  • [Journal Article] Thickness-dependent magnetotransport properties of rocksalt NdO epitaxial thin films: observation of a ferromagnetic phase far above the Curie temperature2023

    • Author(s)
      Saito Daichi、Oka Daichi、Kaminaga Kenichi、Kitamura Miho、Shiga Daisuke、Kumigashira Hiroshi、Fukumura Tomoteru
    • Journal Title

      Journal of Materials Chemistry C

      Volume: 11 Issue: 36 Pages: 12400-12405

    • DOI

      10.1039/d3tc02478d

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] A high-TC heavy rare earth monoxide semiconductor TbO with a more than half-filled 4f orbital2022

    • Author(s)
      Sasaki Satoshi、Oka Daichi、Kaminaga Kenichi、Saito Daichi、Yamamoto Taku、Abe Nobuto、Shimizu Hirokazu、Fukumura Tomoteru
    • Journal Title

      Dalton Transactions

      Volume: 51 Issue: 43 Pages: 16648-16652

    • DOI

      10.1039/d2dt02710k

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Rocksalt CeO epitaxial thin film as a heavy-fermion system transiting from p-type metal to partially compensated n-type metal by 4f delocalization2022

    • Author(s)
      Abe Nobuto、Oka Daichi、Kaminaga Kenichi、Shiga Daisuke、Saito Daichi、Yamamoto Taku、Kimura Noriaki、Kumigashira Hiroshi、Fukumura Tomoteru
    • Journal Title

      Physical Review B

      Volume: 106 Issue: 12 Pages: 125106-125106

    • DOI

      10.1103/physrevb.106.125106

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Rock salt-type HoO epitaxial thin film as a heavy rare-earth monoxide ferromagnetic semiconductor with a Curie temperature above 130 K2022

    • Author(s)
      Amrillah Tahta、Oka Daichi、Shimizu Hirokazu、Sasaki Satoshi、Saito Daichi、Kaminaga Kenichi、Fukumura Tomoteru
    • Journal Title

      Applied Physics Letters

      Volume: 120 Issue: 8 Pages: 082403-082403

    • DOI

      10.1063/5.0081040

    • Related Report
      2022 Annual Research Report 2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Rocksalt-type PrO epitaxial thin film as a weak ferromagnetic Kondo lattice2022

    • Author(s)
      Shimizu Hirokazu、Oka Daichi、Kaminaga Kenichi、Saito Daichi、Yamamoto Taku、Abe Nobuto、Kimura Noriaki、Shiga Daisuke、Kumigashira Hiroshi、Fukumura Tomoteru
    • Journal Title

      Physical Review B

      Volume: 105 Issue: 1 Pages: 014442-014442

    • DOI

      10.1103/physrevb.105.014442

    • Related Report
      2022 Annual Research Report 2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Systematic Application of Extremely Large Strain to Rutile-Type RuO<sub>2</sub>(100) Epitaxial Thin Films on Substrates with Large Lattice Mismatches2021

    • Author(s)
      Fatima Zainab、Oka Daichi、Fukumura Tomoteru
    • Journal Title

      Crystal Growth &amp; Design

      Volume: 21 Issue: 7 Pages: 4083-4089

    • DOI

      10.1021/acs.cgd.1c00377

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Electron localization induced by intrinsic anion disorder in a transition metal oxynitride2021

    • Author(s)
      Oka Daichi、Hirose Yasushi、Nakao Shoichiro、Fukumura Tomoteru、Hasegawa Tetsuya
    • Journal Title

      Communications Physics

      Volume: 4 Issue: 1 Pages: 269-269

    • DOI

      10.1038/s42005-021-00777-z

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Synthesis of Stoichiometric SrTiO3 and Its Carrier Doping from Air-Stable Bimetallic Complexes2021

    • Author(s)
      Oyeka Ebube E.、Oka Daichi、Kwon Eunsang、Fukumura Tomoteru
    • Journal Title

      Inorganic Chemistry

      Volume: 60 Issue: 3 Pages: 1277-1283

    • DOI

      10.1021/acs.inorgchem.0c03457

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed
  • [Presentation] 新希土類単酸化物TmOの薄膜合成と物性2024

    • Author(s)
      吉村 英竜、岡 大地、根岸 真通、佐々木 智視、福村 知昭
    • Organizer
      第71回応用物理学会春季学術講演会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 重希土類単酸化物エピタキシャル薄膜の単相化と電子・磁気物性2024

    • Author(s)
      佐々木 智視、岡 大地、志賀 大亮、中田 勝、和達 大樹、組頭 広志、福村 知昭
    • Organizer
      第71回応用物理学会春季学術講演会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 単相の重希土類単酸化物エピタキシャル薄膜の電子輸送特性2024

    • Author(s)
      佐々木 智視、岡 大地、根岸 真通、福村 知昭
    • Organizer
      第71回応用物理学会春季学術講演会
    • Related Report
      2023 Annual Research Report
  • [Presentation] Epitaxial thin film growth and properties of perovskite-type Ir-doped SrVO32023

    • Author(s)
      Hongming Zhang, Masamichi Negishi, Daichi Oka, and Tomoteru Fukumura
    • Organizer
      令和5年度化学系協会東北大会及び日本化学会東北支部80周年記念国際会議
    • Related Report
      2023 Annual Research Report
  • [Presentation] Synthesis and optical properties of bismuth-based mixed-anion compounds epitaxial thin films2023

    • Author(s)
      Zhengkang Peng, Daichi Oka, Yasushi Hirose, Tomoteru Fukumura
    • Organizer
      第84回応用物理学会秋季学術講演会
    • Related Report
      2023 Annual Research Report
  • [Presentation] Annealing effect on electrical conductivity in Sr3Cr2O7 epitaxial thin films2022

    • Author(s)
      Zhaochen Ma、Daichi Oka、Tomoteru Fukumura
    • Organizer
      第83回応用物理学会秋季学術講演会
    • Related Report
      2022 Annual Research Report
  • [Presentation] 重希土類単酸化物強磁性半導体:DyO・ErOエピタキシャル薄膜2022

    • Author(s)
      佐々木 智視、岡 大地、齋藤 大地、清水 宙一、福村 知昭
    • Organizer
      第83回応用物理学会秋季学術講演会
    • Related Report
      2022 Annual Research Report
  • [Presentation] 岩塩構造テルビウム酸化物TbOの薄膜合成および物性評価2022

    • Author(s)
      佐々木 智視、岡 大地、神永 健一、齋藤 大地、清水 宙一、福村 知昭
    • Organizer
      第38回希土類討論会
    • Related Report
      2022 Annual Research Report
  • [Presentation] Extremely large strain in rutile-type RuO2(100) epitaxial thin films2021

    • Author(s)
      Zainab Fatima, Daichi Oka, and Tomoteru Fukumura
    • Organizer
      第82回応用物理学会秋季学術講演会
    • Related Report
      2021 Annual Research Report
  • [Presentation] PrOエピタキシャル薄膜における多様な磁性相の制御2021

    • Author(s)
      清水 宙一、齋藤 大地、神永 健一、岡 大地、福村 知昭
    • Organizer
      第82回応用物理学会秋季学術講演会
    • Related Report
      2021 Annual Research Report
  • [Presentation] New heavy rare earth ferromagnetic semiconductor: Rocksalt-type TbO2021

    • Author(s)
      Satoshi Sasaki, Daichi Oka, Kenichi Kaminaga, Daichi Saito, Nobuto Abe, Hirokazu Shimizu, and Tomoteru Fukumura
    • Organizer
      Materials Research Meeting 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Thickness Dependence of Magnetotransport Properties of Rocksalt NdO Epitaxial Thin Films2021

    • Author(s)
      Daichi Saito, Daichi Oka, Kenichi Kaminaga, and Tomoteru Fukumura
    • Organizer
      The 4th International Symposium for The Core Research Cluster for Spintronics
    • Related Report
      2020 Annual Research Report
  • [Presentation] 二核錯体を用いた正規組成SrTiO3 エピタキシャル薄膜の合成2021

    • Author(s)
      岡 大地,Ebube E. Oyeka, 權 垠相, 福村 知昭
    • Organizer
      第68回応用物理学会春季学術講演会
    • Related Report
      2020 Annual Research Report
  • [Presentation] 近藤格子PrO エピタキシャル薄膜の低温物性2020

    • Author(s)
      清水 宙一,阿部 展人, 山本 卓, 齋藤 大地, 神永 健一, 岡 大地, 木村 憲彰, 福村 知昭
    • Organizer
      第81回応用物理学会秋季学術講演会
    • Related Report
      2020 Annual Research Report
  • [Presentation] Competing magnetic orders in PrO epitaxial thin films2020

    • Author(s)
      Hirokazu Shimizu,Nobuto Abe, Daichi Saito, Kenichi Kaminaga, Daichi Oka, Noriaki Kimura, Tomoteru Fukumura
    • Organizer
      PASPS-25 第25回半導体におけるスピン工学の基礎と応用
    • Related Report
      2020 Annual Research Report
  • [Remarks] 【研究発表】電気を流し、室温強磁性を示す希土類酸化物を発見-スピントロニクス材料としての応用に期待-

    • URL

      https://www.tmu.ac.jp/news/topics/36694.html

    • Related Report
      2023 Annual Research Report

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Published: 2020-04-28   Modified: 2025-01-30  

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