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Electronic structure of the ultrafast nonequilibrium

Research Project

Project/Area Number 18H01148
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Review Section Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
Research InstitutionThe University of Tokyo

Principal Investigator

石田 行章  東京大学, 物性研究所, リサーチフェロー (30442924)

Project Period (FY) 2018-04-01 – 2023-03-31
Project Status Granted (Fiscal Year 2022)
Budget Amount *help
¥16,250,000 (Direct Cost: ¥12,500,000、Indirect Cost: ¥3,750,000)
Fiscal Year 2022: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2019: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2018: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Keywords超高速現象 / 電子状態 / 時間分解光電子分光 / 仕事関数 / 光電子分光 / トポロジカル相 / 非平衡電子状態 / トポロジカル絶縁体 / 強相関電子系
Outline of Annual Research Achievements

前年度に、従来を1-2桁上回る<1meVの精度で仕事関数を測定できることを発表した(YI et al., Commun. Phys. 2020)。本年度はこの手法を時間分解光電子分光法(TARPES)に応用し、仕事関数を介してフェムト秒域パルスで瞬間的に励起された結晶表面の様子を調べた。
仕事関数を高精度で測定するためには、試料から放出される低速な光電子をきちんと分析できるようにTARPES装置の仕様を調整する必要がある。このために試料に電位を加える電極を通し、さらに真空チャンバー内に不要な構造物を極力排して光電子が飛行する試料と電子分析器の間の真空準位のムラを少なくした。
グラファイトについて、まず0.13 mJ/cm2のポンプ強度で測定を行った。フェルミ準位近傍では光パルスで衝撃的に励起された電子のダイナミクスが明瞭に観測された。一方、光電子分布の低速側にあらわれる仕事関数のカットオフは標準偏差70マイクロeVの精度で動かなかった。
ポンプ強度を上げていくとやがて多光子過程を経て大量の光電子が出てくる。多光子光電子はプローブ光で出る光電子の分布を乱すため、精密なTARPES測定を行う際にはこの放出を抑える必要があるが、仕事関数を測定する目的ではこの限りではない:仕事関数のカットオフをみるための光電子分布は、プローブ光で放出される光電子のものである必要はないためである。すなわち、仕事関数を見る目的に絞れば、通常TARPESでは調べることができない強励起域を調べることができる。
多光子光電子が放出される0.76mJ/cm2までポンプ光の強度を上げて、多光子光電子分布の低速側にあらわれる仕事関数のカットオフを観測し、このエネルギー位置およびカットオフの幅を5.9eV光で出る光電子分布のものと比較した。カットオフのエネルギーは弱励起のものと100マイクロeVの精度の範囲で変化しなかった。

Current Status of Research Progress
Current Status of Research Progress

1: Research has progressed more than it was originally planned.

Reason

精密な仕事関数測定を時間分解光電子分光に組み合わせることが可能となり、固体表層の光ダイナミクスを見る新しいツールを見出した。この他、韓国科学院と共同で、時間分解光電子分光法と高いエネルギー分解能を有するTHz時間分解測定を組み合わせることで、トポロジカル絶縁体の種々の表面状態の連動が見えるようになった。

Strategy for Future Research Activity

精密な仕事関数測定を時間分解光電子分光に組み合わせることが可能となり、固体表層の光ダイナミクスを見る新しいツールを見出した。仕事関数は固体表層にあらわれる表面分極によって形成されるポテンシャル障壁である。近年、表面の分極が固体内部の分極に連動することがトポロジカル物質の研究より指摘されている。新手法をもちいることで、分極の連動に関する新たな知見を得ることを目指す。

Report

(4 results)
  • 2021 Annual Research Report
  • 2020 Annual Research Report
  • 2019 Annual Research Report
  • 2018 Annual Research Report

Research Products

(24 results)

All 2021 2020 2019 2018 Other

All Int'l Joint Research (4 results) Journal Article (13 results) (of which Int'l Joint Research: 11 results,  Peer Reviewed: 13 results,  Open Access: 5 results) Presentation (6 results) (of which Int'l Joint Research: 4 results,  Invited: 6 results) Remarks (1 results)

  • [Int'l Joint Research] Philipps-University(ドイツ)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] ソウル国際大学/韓国科学院(韓国)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] IBS-CCES(韓国)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] Sobolev Inst. of Geology and Mineralogy/Novosibirsk State University/Saint Petersburg State University(ロシア連邦)

    • Related Report
      2019 Annual Research Report
  • [Journal Article] Effect of the sample work function on alkali metal dosing induced electronic structure change2021

    • Author(s)
      Saegyeol Jung, Yukiaki Ishida, Minsoo Kim, Masamichi Nakajima, Shigeyuki Ishida, Hiroshi Eisaki, Woojae Choi, Yong Seung Kwon, Jonathan Denlinger, Toshio Otsu, Yohei Kobayashi, Soonsang Huh, Changyoung Kim
    • Journal Title

      Journal of Electron Spectroscopy and Related Phenomena

      Volume: 249 Pages: 147045-147045

    • DOI

      10.1016/j.elspec.2021.147045

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Ultrafast surface Dirac fermion dynamics of Sb2Te3-based topological insulators2021

    • Author(s)
      K. Sumida, Y. Ishida, J. G_dde, U. H_fer, S. Shin, and A. Kimura
    • Journal Title

      Progress in Surface Science

      Volume: 96 Pages: 100628-100628

    • DOI

      10.1016/j.progsurf.2021.100628

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] A compact and stable incidence-plane-rotating second harmonics detector2021

    • Author(s)
      Kim S. H.、Jung S.、Seok B.、Kim Y. S.、Park H.、Otsu T.、Kobayashi Y.、Kim C.、Ishida Y.
    • Journal Title

      Review of Scientific Instruments

      Volume: 92 Pages: 043905-043905

    • DOI

      10.1063/5.0047337

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Topologically nontrivial phase-change compound GeSb2Te42020

    • Author(s)
      M. Nurmamat, K. Okamoto, S. Zhu, T. V. Menshchikova, I. P. Rusinov, V. O. Korostelev, K. Miyamoto, T. Okuda, T. Miyashita, X. Wang, Y. Ishida, K. Sumida, E. F. Schwier, M. Ye, Z. S. Aliev, M. B. Babanly, I. R. Amiraslanov, E. V. Chulkov, K. A. Kokh, O. E. Tereshchenko, K. Shimada, S. Shin, A. Kimura
    • Journal Title

      ACS Nano

      Volume: 14 Pages: 9059-9065

    • DOI

      10.1021/acsnano.0c04145

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Work function seen with sub-meV precision through laser photoemission2020

    • Author(s)
      Ishida Y.、Jung J. K.、Kim M. S.、Kwon J.、Kim Y. S.、Chung D.、Song I.、Kim C.、Otsu T.、Kobayashi Y.
    • Journal Title

      Communications Physics

      Volume: 3 Pages: 158-158

    • DOI

      10.1038/s42005-020-00426-x

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Observation of unoccupied states of SnTe(111) using pump-probe ARPES measurement2020

    • Author(s)
      Ito Hiroshi、Otaki Yusuke、Tomohiro Yuta、Ishida Yukiaki、Akiyama Ryota、Kimura Akio、Shin Shik、Kuroda Shinji
    • Journal Title

      Phys. Rev. Research

      Volume: 2 Pages: 043120-043120

    • DOI

      10.1103/physrevresearch.2.043120

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Bidirectional surface photovoltage on a topological insulator2019

    • Author(s)
      T. Yoshikawa, K. Sumida, Y. Ishida, J. Chen, M. Nurmamat, K. Akiba, A. Miyake, M. Tokunaga, K. A. Kokh, O. E. Tereshchenko, S. Shin, A. Kimura
    • Journal Title

      Phys. Rev. B

      Volume: 100 Pages: 165311-165311

    • DOI

      10.1103/physrevb.100.165311

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Ultrafast nematic-orbital excitation in FeSe2019

    • Author(s)
      T. Shimojima, Y. Suzuki, A. Nakamura, N. Mitsuishi, S. Kasahara, T. Shibauchi, Y. Matsuda, Y. Ishida, S. Shin, K. Ishizaka
    • Journal Title

      Nature Communications

      Volume: 10 Pages: 1946-1946

    • DOI

      10.1038/s41467-019-09869-5

    • NAID

      120006796398

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Inverted Dirac-electron population in a thermally activated topological insulator2019

    • Author(s)
      K. Sumida, Y. Ishida, T. Yoshikawa, J. Chen, M. Nurmamat, K. A. Kokh, O. E. Tereshchenko, S. Shin, and A. Kimura
    • Journal Title

      Physical Review B

      Volume: 99 Pages: 085302-085302

    • DOI

      10.1103/physrevb.99.085302

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Enhanced photovoltage on the surface of topological insulator by optical aging2018

    • Author(s)
      Tomoki Yoshikawa, Yukiaki Ishida, Kazuki Sumida, Jiahua Chen, Konstantin, A. Kokh, Oleg E. Tereshchenko, Shik Shin, and Akio Kimura
    • Journal Title

      Applied Physics Letters

      Volume: 112 Pages: 192014-192014

    • DOI

      10.1063/1.5008466

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Revealing Solar-Cell Photovoltage Dynamics at the Picosecond Time Scale with Time-Resolved Photoemission Spectroscopy2018

    • Author(s)
      Y. Hazama, Y. Ishida, L. Zhu, C. Kim, S. Shin, H. Akiyama
    • Journal Title

      Phys. Rev. Applied

      Volume: 10 Pages: 034056-034056

    • DOI

      10.1103/physrevapplied.10.034056

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Ultrafast dynamics of unoccupied surface resonances state of Bi2Te2Se2018

    • Author(s)
      Munisa Nurmamat, K. Sumida, Y. Ishida, J. Chen, T. Yoshikawa, E. E. Krasovskii, K. A. Kokh, O. E. Tereshchenko, Shik Shin and Akio Kimura
    • Journal Title

      Physical Review B

      Volume: 97 Pages: 115303-115303

    • DOI

      10.1103/physrevb.97.115303

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Prolonged photo-carriers generated in a massive-and-anisotropic Dirac material2018

    • Author(s)
      Nurmamat Munisa、Ishida Yukiaki、Yori Ryohei、Sumida Kazuki、Zhu Siyuan、Nakatake Masashi、Ueda Yoshifumi、Taniguchi Masaki、Shin Shik、Akahama Yuichi、Kimura Akio
    • Journal Title

      Sci. Rep.

      Volume: 8 Pages: 1-7

    • DOI

      10.1038/s41598-018-27133-6

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] Laser ARPES for the Precise Detection of Slowest Photoelectrons and Work functions2019

    • Author(s)
      Y. Ishida
    • Organizer
      The 17th Japan-Korea symposium on molecular science
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Time-resolved ARPES study of Dirac and topological materials2019

    • Author(s)
      Y. Ishida
    • Organizer
      The 11th International Symposium on Natural Sciences
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Time-resolved ARPES study of Dirac and topological materials2019

    • Author(s)
      Y. Ishida
    • Organizer
      2019 KPS Fall Meeting
    • Related Report
      2019 Annual Research Report
    • Invited
  • [Presentation] Photoelectron work function seen with 1-meV precision2019

    • Author(s)
      Y. Ishida
    • Organizer
      2019 KPS Fall Meeting
    • Related Report
      2019 Annual Research Report
    • Invited
  • [Presentation] “Slit-less” ARPES analyzers: Some utilities and prospects in surface photo-electronics2019

    • Author(s)
      Y. Ishida
    • Organizer
      Momentum Microscopy & Spectroscopy for Materials Science
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Time-resolved ARPES2018

    • Author(s)
      Y. Ishida
    • Organizer
      Korean Physics Society, Spring Meeting
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Remarks] Measuring the work function precisely

    • URL

      https://go.nature.com/30cyXYr

    • Related Report
      2020 Annual Research Report

URL: 

Published: 2018-04-23   Modified: 2022-12-28  

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