Theoretical study on photoinduced dynamics of excitonic insulators

• Project/Area Number: 18K13509
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Osaka University (2022); Institute of Physical and Chemical Research (2018)
• Principal Investigator: Kaneko Tatsuya 大阪大学, 大学院理学研究科, 助教 (30784433)
• Project Period (FY): 2021-11-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2018: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
• Keywords: 励起子絶縁体 / 光誘起ダイナミクス / 非平衡物理 / 非線形光学応答 / 強相関電子系 / 遷移金属カルコゲナイド / 励起子 / 光誘起現象

Outline of Research at the Start

励起子絶縁体はギャップの小さい半導体及びバンドの重なりの小さい半金属においてバンド間クーロン相互作用によって誘起された絶縁体状態であるが、近年にいくつかの候補物質が提案され注目されている。本研究では、励起子絶縁体およびその候補物質の動的な物性の深い理解に向けて、相関効果を取り込んだ光学応答関数の評価や実時間発展の数値計算法なども駆使し、励起子系を筆頭とした相関電子系の光誘起ダイナミクスを理論的に研究する。

Outline of Final Research Achievements

In this project, we investigate photoinduced dynamics of correlated electron systems to understand the nonequilibrium properties of the excitonic insulators driven by the Coulomb interactions. We revealed the dynamical properties of the excitonic insulators including the collective mode of the excitonic order and its linear and nonlinear optical responses. Besides the studies of the excitonic insulators, we also investigate the photoinduced superconducting-like (η-pairing) state and the excitonic effects on high-harmonic generation in strongly correlated electron systems.

Academic Significance and Societal Importance of the Research Achievements

これまでの物性物理はその多くが平衡および線形応答領域において研究が進められてきたため、未開拓な非平衡・非線形応答領域における物性の研究は相関電子系の物理に新たな知見をもたらすものである。本研究で対象とした励起子絶縁体は、その秩序状態が対凝縮の物理のエッセンスを含むなど、物性物理の本質的な側面を多く含んだ舞台となっている。その励起子絶縁体の光誘起による非平衡物性の研究は、量子物質における集団運動の普遍的な性質の理解にもつながる有意義なものである。また、非線形光学応答や物性の超高速な外場制御は基礎だけでなく応用の観点からも重要である。

Research Products

• [Int'l Joint Research] Columbia University/Flatiron Institute(米国)
• [Int'l Joint Research] University of Fribourg/Paul Scherrer Institute(スイス)
• [Int'l Joint Research] Jozef Stefan Institute(スロベニア)
• [Int'l Joint Research] Tsinghua University(中国)
• [Int'l Joint Research] IFW Dresden/TU Dresden(ドイツ)
• [Int'l Joint Research] SISSA(イタリア)
• [Journal Article] Spin, Charge, and η-Spin Separation in One-Dimensional Photodoped Mott Insulators (2023)
  • Author(s): Murakami Yuta、Takayoshi Shintaro、Kaneko Tatsuya、Lauchli Andreas M.、Werner Philipp
  • Journal Title: Physical Review Letters Volume: 130 Issue: 10 Pages: 106501-106501
  • DOI: 10.1103/physrevlett.130.106501
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Two-step Mott transition in Ni(S,Se)2: μSR studies and charge-spin percolation model (2022)
  • Author(s): Q. Sheng, T. Kaneko, K. Yamakawa, Z. Guguchia, Z. Gong, G. Zhao, G. Dai, C. Jin, S. Guo, L. Fu, Y. Gu, F. Ning, Y. Cai, K. M. Kojima, J. Beare, G. M. Luke, S. Miyasaka, M. Matsuura, S.-i. Shamoto, T. U. Ito, W. Higemoto, A. Gauzzi, Y. Klein, Y. J. Uemura
  • Journal Title: Physical Review Research Volume: 4 Issue: 3
  • DOI: 10.1103/physrevresearch.4.033172
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Excitonic effects on high-harmonic generation in Mott insulators (2022)
  • Author(s): Udono Mina、Sugimoto Koudai、Kaneko Tatsuya、Ohta Yukinori
  • Journal Title: Physical Review B Volume: 105 Issue: 24
  • DOI: 10.1103/physrevb.105.l241108
  • Peer Reviewed
• [Journal Article] Second-order magnetic responses in quantum magnets: Magnetization under ac magnetic fields (2022)
  • Author(s): Kaneko Tatsuya、Murakami Yuta、Takayoshi Shintaro、Millis Andrew J.
  • Journal Title: Physical Review B Volume: 105 Issue: 19 Pages: 195126-195126
  • DOI: 10.1103/physrevb.105.195126
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Spin texture and spin current in excitonic phases of the two-band Hubbard model (2019)
  • Author(s): Nishida Hisao, Miyakoshi Shohei, Kaneko Tatsuya, Sugimoto Koudai, Ohta Yukinori
  • Journal Title: Physical Review B Volume: 99 Issue: 3
  • DOI: 10.1103/physrevb.99.035119
  • Peer Reviewed
• [Journal Article] Honeycomb lattice type charge density wave associated with interlayer Cu ions ordering in 1T-CuxTiSe2 (2019)
  • Author(s): Kitou Shunsuke、Kobayashi Shintaro、Kaneko Tatsuya、Katayama Naoyuki、Yunoki Seiji、Nakamura Toshikazu、Sawa Hiroshi
  • Journal Title: Physical Review B Volume: 99 Issue: 8 Pages: 081111-081111
  • DOI: 10.1103/physrevb.99.081111
  • NAID: 120006643273
  • Peer Reviewed
• [Journal Article] Photoinduced η Pairing in the Hubbard Model (2019)
  • Author(s): Kaneko Tatsuya、Shirakawa Tomonori、Sorella Sandro、Yunoki Seiji
  • Journal Title: Physical Review Letters Volume: 122 Issue: 7
  • DOI: 10.1103/physrevlett.122.077002
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Exciton-phonon cooperative mechanism of the triple-q charge-density-wave and antiferroelectric electron polarization in TiSe2 (2018)
  • Author(s): Kaneko Tatsuya, Ohta Yukinori, Yunoki Seiji
  • Journal Title: Physical Review B Volume: 97 Issue: 15
  • DOI: 10.1103/physrevb.97.155131
  • Peer Reviewed
• [Journal Article] Strong Coupling Nature of the Excitonic Insulator State in Ta2NiSe5 (2018)
  • Author(s): Sugimoto Koudai, Nishimoto Satoshi, Kaneko Tatsuya, Ohta Yukinori
  • Journal Title: Physical Review Letters Volume: 120 Issue: 24
  • DOI: 10.1103/physrevlett.120.247602
  • NAID: 130007735297
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 電荷移動型絶縁体における励起子-スピン相互作用 (2023)
  • Author(s): 金子竜也, 村上雄太, Denis Golez, Zhiyuan Sun, Andrew J. Millis
  • Organizer: 日本物理学会（2023年春季大会）
• [Presentation] Exciton-spin interaction in charge-transfer insulators (2023)
  • Author(s): Tatsuya Kaneko, Yuta Murakami, Denis Golez, Zhiyuan Sun, Andrew J. Millis
  • Organizer: APS March Meeting
  • Int'l Joint Research
• [Presentation] Hubbard模型における光誘起η-pairing状態の理論的研究 (2019)
  • Author(s): 金子竜也、白川知功、柚木清司
  • Organizer: 日本物理学会（2019年年次大会）
• [Presentation] 拡張Falicov-Kimball模型における電子-電子ペアリングの光誘起 (2019)
  • Author(s): 藤内亮、金子竜也、柚木清司、太田幸則
  • Organizer: 日本物理学会（2019年年次大会）
• [Presentation] Pulse-induced η-pairing correlation in a Mott-Hubbard system (2018)
  • Author(s): Kaneko Tatsuya、Shirakawa Tomonori、Sorella Sandro、Yunoki Seiji
  • Organizer: International Conference on Magnetism
  • Int'l Joint Research
• [Presentation] Hubbard模型における光誘起η-pairing状態のスペクトル構造 (2018)
  • Author(s): 金子竜也、白川知功、柚木清司
  • Organizer: 日本物理学会（2018年秋季大会）