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Development of the microscopic theory on external-field responses of excitonic insulators

Research Project

Project/Area Number 15H06093
Research Category

Grant-in-Aid for Research Activity Start-up

Allocation TypeSingle-year Grants
Research Field Condensed matter physics II
Research InstitutionChiba University

Principal Investigator

Sugimoto Koudai  千葉大学, 先進科学センター, 特任助教 (70756072)

Project Period (FY) 2015-08-28 – 2017-03-31
Project Status Completed (Fiscal Year 2016)
Budget Amount *help
¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2015: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords励起子絶縁体 / 遷移金属カルコゲナイド / コバルト酸化物 / 励起子相 / 磁化率 / 光学伝導度 / 集団励起 / 物性理論 / 励起子 / 強相関電子系 / 計算物理 / 層状遷移金属カルコゲナイド / 超音波吸収 / 核磁気共鳴 / 量子干渉 / 反磁性
Outline of Final Research Achievements

An excitonic insulator is a system where electrons and holes spontaneously form pairs (excitons) in a semiconductor or a semimetal and the pairs go into quantum condensation. We have focused on transition-metal chalcogenide Ta2NiSe5 known as a candidate material of an excitonic insulator, and have clarified the behaviors of the microscopic quantum interferences in the ultrasonic attenuation rate and the NMR relaxation rate, the diamagnetic susceptibility, and the optical conductivity from the perspective of the excitonic condensation in it. We have also shown that in cobalt oxide Pr0.5Ca0.5CoO3 the magnetic-multipole order emerges in the excitonic phase, and have studied its low-energy excaitation spectra.

Report

(3 results)
  • 2016 Annual Research Report   Final Research Report ( PDF )
  • 2015 Annual Research Report
  • Research Products

    (11 results)

All 2017 2016 2015

All Journal Article (5 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 5 results,  Acknowledgement Compliant: 5 results,  Open Access: 1 results) Presentation (6 results) (of which Int'l Joint Research: 1 results)

  • [Journal Article] Low-energy excitation spectra in the excitonic phase of cobalt oxides2017

    • Author(s)
      Tomoki Yamaguchi, Koudai Sugimoto, and Yukinori Ohta
    • Journal Title

      Journal of the Physical Society of Japan

      Volume: 86 Issue: 4 Pages: 043701-043701

    • DOI

      10.7566/jpsj.86.043701

    • NAID

      210000134323

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Coherence Factors and Quantum Interferences in Excitonic Condensation of Ta2NiSe52017

    • Author(s)
      Koudai Sugimoto, Tatsuya Kaneko, and Yukinori Ohta
    • Journal Title

      Journal of Physics: Conference Series

      Volume: 807 Issue: 11 Pages: 112001-112001

    • DOI

      10.1088/1742-6596/807/11/112001

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] 相関電子系における励起子凝縮の物理の新展開2017

    • Author(s)
      太田幸則、金子竜也、杉本高大
    • Journal Title

      固体物理

      Volume: 52 Pages: 119-137

    • NAID

      40021137326

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Orbital diamagnetic susceptibility in excitonic condensation phase2016

    • Author(s)
      Koudai Sugimoto and Yukinori Ohta
    • Journal Title

      Physical Review B

      Volume: 94 Issue: 8 Pages: 085111-085111

    • DOI

      10.1103/physrevb.94.085111

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Microscopic quantum interference in excitonic condensation of Ta2NiSe52016

    • Author(s)
      K. Sugimoto, T. Kaneko, and Y. Ohta
    • Journal Title

      Physical Review B

      Volume: 93 Issue: 4

    • DOI

      10.1103/physrevb.93.041105

    • Related Report
      2015 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Presentation] GW近似による励起子絶縁体Ta2NiSe5の電子状態計算2017

    • Author(s)
      杉本高大、西本理、金子竜也、太田幸則
    • Organizer
      日本物理学会第72回年次大会
    • Place of Presentation
      大阪大学豊中キャンパス
    • Year and Date
      2017-03-18
    • Related Report
      2016 Annual Research Report
  • [Presentation] Ta2NiSe5 における光学伝導度と磁化率2016

    • Author(s)
      杉本高大、金子竜也、太田幸則
    • Organizer
      日本物理学会2016年秋季大会
    • Place of Presentation
      金沢大学角間キャンパス
    • Year and Date
      2016-09-13
    • Related Report
      2016 Annual Research Report
  • [Presentation] Coherence Factors and Quantum Interferences in Excitonic Condensation of Ta2NiSe52016

    • Author(s)
      Koudai Sugimoto, Tatsuya Kaneko, Yukinori Ohta
    • Organizer
      International Conference on Strongly Correlated Electron Systems 2016
    • Place of Presentation
      the International Conference Center of Zhejiang University (Zi-Jin-Gang Campus), Hangzhou, China
    • Year and Date
      2016-05-10
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 二軌道ハバード模型の励起子相における軌道磁化率2016

    • Author(s)
      杉本高大、太田幸則
    • Organizer
      日本物理学会第71回年次大会(2016年)
    • Place of Presentation
      東北学院大学泉キャンパス
    • Year and Date
      2016-03-19
    • Related Report
      2015 Annual Research Report
  • [Presentation] Ta2NiSe5の励起子相における量子干渉効果2015

    • Author(s)
      杉本高大
    • Organizer
      東京大学物性研究所短期研究会「低次元電子系におけるエキシトニック相の新展開」
    • Place of Presentation
      東京大学物性研究所
    • Year and Date
      2015-11-26
    • Related Report
      2015 Annual Research Report
  • [Presentation] 励起子絶縁体Ta2NiSe5におけるコヒーレンスピーク2015

    • Author(s)
      杉本高大、金子竜也、太田幸則
    • Organizer
      日本物理学会2015年秋季大会
    • Place of Presentation
      関西大学千里山キャンパス
    • Year and Date
      2015-09-16
    • Related Report
      2015 Annual Research Report

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Published: 2015-08-26   Modified: 2020-05-15  

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