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Skewed electronic band structure of ferroelectric oxide induced by the electric polarization

Research Project

Project/Area Number 19K05271
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 29020:Thin film/surface and interfacial physical properties-related
Research InstitutionOkayama University

Principal Investigator

Kano Jun  岡山大学, 自然科学学域, 准教授 (50375408)

Project Period (FY) 2019-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Keywords強誘電体 / バンド構造 / 角度分解光電子分光法 / 薄膜 / 電気分極 / 角度分解硬X線光電子分光 / 半導体物性 / 電子構造
Outline of Research at the Start

近年,新規強誘電体デバイスとしてメモリが提案され,その動作原理がバンド傾斜構造を用いて解釈されている。バンド傾斜する方向は電気分極向きに対応するため,電子の能動的な移動が制御可能なシステムとなる。本研究では,分極向きが揃ったエピタキシャルな強誘電体酸化物薄膜をパルスレーザー堆積法により合成し,その試料に対し分極方向への深さスキャン可能な角度分解硬X線光電子分光実験によるバンド傾斜の直接観測を試みる。バンド傾斜観測に成功すれば,強誘電体の分極形成機構がバンド傾斜を特徴とする電子構造から解明でき,強誘電体中の特異な電子挙動を使ったメモリの精密設計が可能となる。

Outline of Final Research Achievements

Angle-resolved hard x-ray photoemission spectroscopy (AR-HAXPES) has been performed on a skewed electronic structure in ferroelectric thin films. The slope of the skewed band could be changed by switching the polarization. In our experiment, an electronic structure skewed by the electric polarization of ferroelectric is revealed by the binding energy shift of atomic orbitals. All atomic orbitals show similar behaviors, but the magnitude of the energy shift is different. We attributed the electric polarization in the ion crystal to the atomic contribution. Born effective charges, which are different from nominal ionic charges, are defined by the actual amplitude of the polarization divided by the ionic displacement. We found that the magnitude of the energy shift of each atomic orbital has a good correlation with the Born effective charge. These findings lead to a better understanding of the origin of electric polarization.

Academic Significance and Societal Importance of the Research Achievements

スマートフォンなどに用いられるコンデンサーの基幹材料である強誘電体は,電荷を蓄えられるだけでなく,ダイオードのような電気の流れ方をすることが最近わかってきた。その動作原理は,「傾斜したバンド構造」によるものと考えられてきたが,実証した例はなかった。我々は放射光を用いた実験により,初めて傾斜したバンド構造の直接観測に成功した。今回の成果により,強誘電体を用いた新しいデバイス開発の進展が期待される。

Report

(4 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (11 results)

All 2021 2020 2019 Other

All Int'l Joint Research (1 results) Journal Article (8 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 8 results,  Open Access: 2 results) Presentation (2 results) (of which Int'l Joint Research: 2 results,  Invited: 1 results)

  • [Int'l Joint Research] CentraleSupelec(フランス)

    • Related Report
      2019 Research-status Report
  • [Journal Article] High valence states of Pd supported on ferroelectric BaTiO<sub>3</sub> driven by electric polarization2021

    • Author(s)
      Yoshida Tasuku、Kano Jun、Mizumaki Masaichiro、Tamenori Yusuke、Nitta Kiyofumi、Kato Kazuo、Hinokuma Satoshi、Oshime Norihiro、Hirose Satoshi、Mikami Hitoshi、Ikeda Naoshi、Fujii Tatsuo、Nishina Yuta、Okubo Tomoko
    • Journal Title

      Applied Physics Letters

      Volume: 119 Issue: 9 Pages: 092904-092904

    • DOI

      10.1063/5.0066289

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Skewing of electronic band along the direction of electric polarization in ferroelectrics2021

    • Author(s)
      Jun Kano, Norihiro Oshime
    • Journal Title

      SPring-8/SACLA Research Frontiers 2020

      Volume: 2020 Pages: 58-59

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Single domain growth and charge ordering of epitaxial YbFe<sub>2</sub>O<sub>4</sub> films2021

    • Author(s)
      Sakagami Takumi、Ota Reika、Kano Jun、Ikeda Naoshi、Fujii Tatsuo
    • Journal Title

      CrystEngComm

      Volume: 23 Issue: 35 Pages: 6163-6170

    • DOI

      10.1039/d1ce00834j

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Light reflectance and photoelectron yield spectroscopy enable acceptor level measurement in p-type Ba1-xTiO3 semiconductor2021

    • Author(s)
      Fujii Saya、Kano Jun、Oshime Norihiro、Higuchi Tohru、Nishina Yuta、Fujii Tatsuo、Ikeda Naoshi、Ota Hiromi
    • Journal Title

      Journal of Applied Physics

      Volume: 129 Issue: 8 Pages: 084105-084105

    • DOI

      10.1063/5.0033761

    • Related Report
      2021 Annual Research Report 2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Surface Electron-Ion Mixed Conduction of BaTiO3-δ Thin Film with Oxygen Vacancies2021

    • Author(s)
      Takada Tomoasa、Fujita Takeshi、Imagawa Takehiro、Yamamoto Emi、Kano Jun、Shiga Daisuke、Horiba Koji、Kumigashira Hiroshi、Higuchi Tohru
    • Journal Title

      Journal of the Physical Society of Japan

      Volume: 90 Issue: 1 Pages: 014707-014707

    • DOI

      10.7566/jpsj.90.014707

    • NAID

      40022452842

    • Related Report
      2021 Annual Research Report 2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] 強誘電体の電子構造─反電場効果により傾斜するバンド構造─2021

    • Author(s)
      狩野 旬 , 押目 典宏 , 池永 英司 , 安井 伸太郎 , 日隈 聡士 , 保井 晃
    • Journal Title

      セラミックス

      Volume: 56 Pages: 463-466

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] 強誘電体チタン酸バリウムの電気分極に誘起された バンド傾斜構造の観測2021

    • Author(s)
      押目典宏 , 狩野旬
    • Journal Title

      放射光

      Volume: 34 Pages: 225-234

    • NAID

      40022667534

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Skewed electronic band structure induced by electric polarization in ferroelectric BaTiO32020

    • Author(s)
      Oshime Norihiro、Kano Jun、Ikenaga Eiji、Yasui Shintaro、Hamasaki Yosuke、Yasuhara Sou、Hinokuma Satoshi、Ikeda Naoshi、Janolin Pierre-Eymeric、Kiat Jean-Michel、Itoh Mitsuru、Yokoya Takayoshi、Fujii Tatsuo、Yasui Akira、Osawa Hitoshi
    • Journal Title

      Scientific Reports

      Volume: 10 Issue: 1 Pages: 10702-10702

    • DOI

      10.1038/s41598-020-67651-w

    • NAID

      120006872416

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] Skewed Electronic Band Structure of Ferroelectric BaTiO3 Studied by Angle-resolved Hard X-ray Photoemission Spectroscopy2020

    • Author(s)
      Jun Kano, Norihiro Oshime, Eiji Ikenaga, Shintaro Yasui, Yosuke Hamasaki, Sou Yasuhara, Satoshi Hinokuma, Naoshi Ikeda, Pierre-Eymeric Janolin, Jean-Michel Kiat, Mitsuru Itoh, Takayoshi Yokoya, Tatsuo Fujii, Akira Yasui, and Hitoshi Osawa
    • Organizer
      The international workshop for synergetic collaboration between material and synchrotron science through IMR-MAX IV joint research (IMR+MAX IV 2020)
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Skewed core level atomic orbitals in ferroelectric BaTiO3 induced by electric polarization2019

    • Author(s)
      Jun Kano, Norihiro Oshime, Eiji Ikenaga, Shintaro Yasui, Yosuke Hamasaki, Sou Yasuhara, Satoshi Hinokuma, Naoshi Ikeda, Pierre-Eymeric Janolin, Jean-Michel Kiat, Mitsuru Itoh, Takayoshi Yokoya, Tatsuo Fujii, Akira Yasui, and Hitoshi Osawa
    • Organizer
      HAXPES2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research

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Published: 2019-04-18   Modified: 2023-01-30  

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