Frontiers in topological material science

• Project/Area Number: 18H03678
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: 村上 修一 東京工業大学, 理学院, 教授 (30282685)
• Co-Investigator(Kenkyū-buntansha): 平山 元昭 国立研究開発法人理化学研究所, 創発物性科学研究センター, ユニットリーダー (70761005)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Granted (Fiscal Year 2021)
• Budget Amount: ¥37,700,000 (Direct Cost: ¥29,000,000、Indirect Cost: ¥8,700,000); Fiscal Year 2021: ¥7,930,000 (Direct Cost: ¥6,100,000、Indirect Cost: ¥1,830,000); Fiscal Year 2020: ¥7,930,000 (Direct Cost: ¥6,100,000、Indirect Cost: ¥1,830,000); Fiscal Year 2019: ¥7,930,000 (Direct Cost: ¥6,100,000、Indirect Cost: ¥1,830,000); Fiscal Year 2018: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
• Keywords: 物性理論 / トポロジー / 磁性 / スピンエレクトロニクス / トポロジカル絶縁体

Outline of Annual Research Achievements

第一に、系に電流を流すと磁化が生じる効果(kinetic magnetoelectric効果)がトポロジカル絶縁体においても起こることを理論的に提案した。これは先行研究では金属において研究されてきたが、本研究においてトポロジカル絶縁体を考えると、表面の金属状態を流れる電流がらせん状に流れるために軌道磁化が生じることを理論的に示した。さらにこの効果を示すためにはトポロジカル絶縁体が空間反転対称性を破っている必要があることを示し、そのような物質の候補を与えた。
第二に、非エルミート１次元系のバンド構造とトポロジーに関する基礎理論構築と異常な物性の提案を進めた。BdG型と呼ばれる形式のボーズ粒子系では、エルミート性と非エルミート性が一つの系で共存していることを示した。また空間反転対称性のある系では、非エルミート表皮モードの侵入長が系の大きさに比例するという特異な振る舞いを示すことを示した。
第三に、カイラルフォノンと呼ばれるフォノンの回転自由度について基礎理論を構築した。特にk=0でのゴールドストーンモードであるゼロ周波数のフォノンに対して時間反転対称性を破ってギャップを開くとき、その角運動量は系によらず普遍的な値をとることを示した。第四に、前年度に引き続いてアパタイト電子化物が高次トポロジカル相になるという理論提案や、SSH模型などに代表される系で、量子化された分極に起因する異常な誘電性の理論的提案を行った。
最後に、実験グループと協力して、alpha-RuCl3でのフォノンモードに現れる特異性、RbV3Sb5などでの特異な電荷密度波、BaPtGeのフォノンでの４重ワイル点の観測など様々な成果を、理論の立場からサポートした。

Current Status of Research Progress

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

Reason

当初の研究計画になかったさまざまな研究の展開ができ、さらに今後の研究につながっていく可能性を拓くことができた。例えば非エルミート系については、我々の構築したnon-Bloch理論の応用例が、特異なスケーリング則やBdG系での特異な物性などの発見につながった。またトポロジカル絶縁体でのkinetic magnetoelectric効果についても、予想以上にまとまった一般的な成果を得ることができ、物質提案まで行うことができた。また実験グループとの共同研究も、我々の研究展開に伴い新たに始めたものであり、そこからさまざまな成果をえることができた。このようにさまざまな面で当初以上に研究が進展したといえる。

Strategy for Future Research Activity

カイラルフォノンの研究や非エルミート系の研究は今後もさまざまな展開が期待でき、引き続き理論研究を行う。基礎理論の構築と、実際の系や物質での実現例の探索を並行して行う。また、今後もトポロジカル物質および物性の開拓を行う。特にトポロジカルな分極は原子軌道からずれた位置に重心を持つ電子雲に対応し、化学結合等の実空間描像とも親和性が高い。群論に基づいた新奇トポロジカル相として有望な空間群の選定、および既約表現に基づく波数空間の電子構造の設計から、電子化物などの実空間において非自明な結合性を示す新材料の設計を目指す。

Research Products

• [Int'l Joint Research] Oak Ridge National Laboratory/Brookhaven National Laboratory/Argonne National Laboratory(米国)
• [Int'l Joint Research] University of Cambridge(英国)
• [Int'l Joint Research] Institute of Physics/Renmin University of China(中国)
• [Int'l Joint Research] マインツ大学(ドイツ)
• [Journal Article] Fractional hinge and corner charges in various crystal shapes with cubic symmetry (2022)
  • Author(s): Naito Katsuaki、Takahashi Ryo、Watanabe Haruki、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 105 Pages: 045126-045126
  • DOI: 10.1103/physrevb.105.045126
  • Peer Reviewed
• [Journal Article] Chiral phonons and pseudoangular momentum in nonsymmorphic systems (2022)
  • Author(s): Zhang Tiantian、Murakami Shuichi
  • Journal Title: Physical Review Research Volume: 4
  • DOI: 10.1103/physrevresearch.4.l012024
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rotoinversion-symmetric bulk-hinge correspondence and its applications to higher-order Weyl semimetals (2022)
  • Author(s): Tanaka Yutaro、Takahashi Ryo、Okugawa Ryo、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 105 Pages: 115119-115119
  • DOI: 10.1103/physrevb.105.115119
  • Peer Reviewed
• [Journal Article] Anisotropic Penetration Depths of Corner States in a Higher-Order Topological Insulator (2021)
  • Author(s): Arai Nobuhiro、Murakami Shuichi
  • Journal Title: J. Phys. Soc. Jpn. Volume: 90 Issue: 7 Pages: 074711-074711
  • DOI: 10.7566/jpsj.90.074711
  • NAID: 40022620554
  • ISSN: 0031-9015, 1347-4073
  • Peer Reviewed
• [Journal Article] Observation of Unconventional Charge Density Wave without Acoustic Phonon Anomaly in Kagome Superconductors AV3Sb5 (A=Rb,Cs) (2021)
  • Author(s): Li Haoxiang、Zhang T. T.、Yilmaz T.、Pai Y. Y.、Marvinney C. E.、Said A.、Yin Q. W.、Gong C. S.、Tu Z. J.、Vescovo E.、Nelson C. S.、Moore R. G.、Murakami S.、Lei H. C.、Lee H. N.、Lawrie B. J.、Miao H.
  • Journal Title: Physical Review X Volume: 11 Pages: 031050-031050
  • DOI: 10.1103/physrevx.11.031050
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Giant phonon anomalies in the proximate Kitaev quantum spin liquid α-RuCl3 (2021)
  • Author(s): Li Haoxiang、Zhang T. T.、Said A.、Fabbris G.、Mazzone D. G.、Yan J. Q.、Mandrus D.、Halasz Gabor B.、Okamoto S.、Murakami S.、Dean M. P. M.、Lee H. N.、Miao H.
  • Journal Title: Nature Communications Volume: 12 Pages: 3513-3513
  • DOI: 10.1038/s41467-021-23826-1
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] General corner charge formula in two-dimensional Cn-symmetric higher-order topological insulators (2021)
  • Author(s): Takahashi Ryo、Zhang Tiantian、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 103 Pages: 205123-205123
  • DOI: 10.1103/physrevb.103.205123
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Kinetic magnetoelectric effect in topological insulators (2021)
  • Author(s): Osumi Ken、Zhang Tiantian、Murakami Shuichi
  • Journal Title: Communications Physics Volume: 4 Pages: 211-211
  • DOI: 10.1038/s42005-021-00702-4
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Predicting topological materials: symmetry-based indicator theories and beyond (2021)
  • Author(s): Zhang Tiantian、Murakami Shuichi
  • Journal Title: Journal of Physics D: Applied Physics Volume: 54 Pages: 414002-414002
  • DOI: 10.1088/1361-6463/ac13f4
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP (2021)
  • Author(s): Peng Bo、Murakami Shuichi、Monserrat Bartomeu、Zhang Tiantian
  • Journal Title: npj Computational Materials Volume: 7 Pages: 195-195
  • DOI: 10.1038/s41524-021-00667-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Unique surface-state connection between Weyl and nodal ring fermions in ferromagnetic material Cs2MoCl6 (2021)
  • Author(s): Zhang Tiantian、Hara Daisuke、Murakami Shuichi
  • Journal Title: Physical Review Research Volume: 3
  • DOI: 10.1103/physrevresearch.3.l042037
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Observation of a chiral wave function in the twofold-degenerate quadruple Weyl system BaPtGe (2021)
  • Author(s): Li Haoxiang、Zhang Tiantian、Said A.、Fu Y.、Fabbris G.、Mazzone D. G.、Zhang J.、Lapano J.、Lee H. N.、Lei H. C.、Dean M. P. M.、Murakami S.、Miao H.
  • Journal Title: Physical Review B Volume: 103 Pages: 184301-184301
  • DOI: 10.1103/physrevb.103.184301
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Theoretical analysis of glide-Z₂ magnetic topological photonic crystals (2021)
  • Author(s): Kim Heejae、Cheng Hengbin、Lu Ling、Murakami Shuichi
  • Journal Title: Optics Express Volume: 29 Pages: 31164-31164
  • DOI: 10.1364/oe.439590
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Scaling rule for the critical non-Hermitian skin effect (2021)
  • Author(s): Yokomizo Kazuki、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 104 Pages: 165117-165117
  • DOI: 10.1103/physrevb.104.165117
  • Peer Reviewed
• [Journal Article] Non-Bloch band theory in bosonic Bogoliubov?de Gennes systems (2021)
  • Author(s): Yokomizo Kazuki、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 103 Pages: 165123-165123
  • DOI: 10.1103/physrevb.103.165123
  • Peer Reviewed
• [Journal Article] Higher-order topological crystalline insulating phase and quantized hinge charge in topological electride apatite (2020)
  • Author(s): Hirayama Motoaki、Takahashi Ryo、Matsuishi Satoru、Hosono Hideo、Murakami Shuichi
  • Journal Title: Physical Review Research Volume: 2 Pages: 043131-043131
  • DOI: 10.1103/physrevresearch.2.043131
  • Peer Reviewed / Open Access
• [Journal Article] Anomalous dielectric response in insulators with the π Zak phase (2020)
  • Author(s): Aihara Yusuke、Hirayama Motoaki、Murakami Shuichi
  • Journal Title: Physical Review Research Volume: 2 Pages: 033224-033224
  • DOI: 10.1103/physrevresearch.2.033224
  • Peer Reviewed / Open Access
• [Journal Article] Berry curvature for magnetoelastic waves (2020)
  • Author(s): Okamoto Akihiro、Murakami Shuichi、Everschor-Sitte Karin
  • Journal Title: Physical Review B Volume: 101 Pages: 064424-064424
  • DOI: 10.1103/physrevb.101.064424
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Appearance of hinge states in second-order topological insulators via the cutting procedure (2020)
  • Author(s): Tanaka Yutaro、Takahashi Ryo、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 101 Pages: 115120-115120
  • DOI: 10.1103/physrevb.101.115120
  • Peer Reviewed
• [Journal Article] Bulk-edge and bulk-hinge correspondence in inversion-symmetric insulators (2020)
  • Author(s): Takahashi Ryo、Tanaka Yutaro、Murakami Shuichi
  • Journal Title: Physical Review Research Volume: 2 Pages: 013300-013300
  • DOI: 10.1103/physrevresearch.2.013300
  • NAID: 130008154196
  • Peer Reviewed / Open Access
• [Journal Article] Radial spin texture in elemental tellurium with chiral crystal structure (2020)
  • Author(s): M. Sakano, M. Hirayama, T. Takahashi, S. Akebi, M. Nakayama, K. Kuroda, K. Taguchi, T. Yoshikawa, K. Miyamoto, T. Okuda, K. Ono, H. Kumigashira, T. Ideue, Y. Iwasa, N. Mitsuishi, K. Ishizaka, S. Shin, T. Miyake, S. Murakami, T. Sasagawa, and Takeshi Kondo
  • Journal Title: Physical Review Letters Volume: 124 Pages: 136404-136404
  • DOI: 10.1103/physrevlett.124.136404
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Topological band structure of surface acoustic waves on a periodically corrugated surface (2019)
  • Author(s): Inoue Tomohiro、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 99 Pages: 195443-195443
  • DOI: 10.1103/physrevb.99.195443
  • Peer Reviewed
• [Journal Article] Non-Bloch Band Theory of Non-Hermitian Systems (2019)
  • Author(s): Yokomizo Kazuki、Murakami Shuichi
  • Journal Title: Physical Review Letters Volume: 123 Pages: 066404-066404
  • DOI: 10.1103/physrevlett.123.066404
  • Peer Reviewed
• [Journal Article] Topological linelike bound states in the continuum (2019)
  • Author(s): Takeichi Manabu、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 99 Pages: 035128-035128
  • DOI: 10.1103/physrevb.99.035128
  • Peer Reviewed
• [Journal Article] Topological semimetal phases manifested in transition metal dichalcogenides intercalated with 3d metals (2019)
  • Author(s): Inoshita Takeshi、Hirayama Motoaki、Hamada Noriaki、Hosono Hideo、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 100 Pages: 121112-121112
  • DOI: 10.1103/physrevb.100.121112
  • Peer Reviewed
• [Journal Article] Glide-symmetric magnetic topological crystalline insulators with inversion symmetry (2019)
  • Author(s): Kim Heejae、Shiozaki Ken、Murakami Shuichi
  • Journal Title: Physical Review B Volume: 100 Pages: 165202-165202
  • DOI: 10.1103/physrevb.100.165202
  • Peer Reviewed
• [Journal Article] Pressure-induced topological phase transition in noncentrosymmetric elemental tellurium (2019)
  • Author(s): Toshiya Ideue, Motoaki Hirayama, Hiroaki Taiko, Takanari Takahashi, Masayuki Murase, Takashi Miyake, Shuichi Murakami, Takao Sasagawa, Yoshihiro Iwasa
  • Journal Title: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Volume: 116 Pages: 25530-25534
  • DOI: 10.1073/pnas.1905524116
  • Peer Reviewed
• [Journal Article] Nodal-line semimetal superlattices (2018)
  • Author(s): Yokomizo Kazuki、Yamada Hiroaki、Murakami Shuichi
  • Journal Title: Journal of Physics: Condensed Matter Volume: 30 Pages: 505301-505301
  • DOI: 10.1088/1361-648x/aaeabe
  • Peer Reviewed / Open Access
• [Journal Article] Electrides as a New Platform of Topological Materials (2018)
  • Author(s): Hirayama Motoaki、Matsuishi Satoru、Hosono Hideo、Murakami Shuichi
  • Journal Title: Physical Review X Volume: 8 Pages: 031067-031067
  • DOI: 10.1103/physrevx.8.031067
  • NAID: 130008146203
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] カイラル結晶でのカイラル輸送現象と物質への応用 (2021)
  • Author(s): 村上修一
  • Organizer: 日本物理学会年次大会
• [Presentation] Generalized corner-charge formula in higher-order topological insulators and its application to one-dimensional electrides (2021)
  • Author(s): 村上修一
  • Organizer: APS March Meeting 2021
  • Int'l Joint Research
• [Presentation] Theoretical approaches to topological materials (2021)
  • Author(s): 村上修一
  • Organizer: The 4th Symposium for The Core Research Cluster for Materials Science and the 3rd Symposium on International Joint Graduate Program in Materials Science,
  • Int'l Joint Research / Invited
• [Presentation] トポロジカル物質概論：現状と展望 (2021)
  • Author(s): 村上修一
  • Organizer: 第245 回 ＪＯＥＭ研究会「トポロジカル絶縁体」
  • Invited
• [Presentation] Bloch Band Theory for Non-Hermitian Systems (2021)
  • Author(s): 村上修一
  • Organizer: YITP workshop YITP-W-21-11"Theoretical studies of topological phases of matter“
  • Int'l Joint Research / Invited
• [Presentation] 非エルミート系のブロッホ理論とトポロジー (2021)
  • Author(s): 村上修一
  • Organizer: 京都大学物理学第一教室談話会
  • Invited
• [Presentation] New horizons of topological materials (2021)
  • Author(s): 村上修一
  • Organizer: NIMS Week
  • Int'l Joint Research / Invited
• [Presentation] Kinetic magnetoelectric effect in topological insulators (2021)
  • Author(s): 村上修一
  • Organizer: 722. WE-Heraeus-Seminar "Hybrid Solid State Quantum Circuits, Sensors, and Metrology"
  • Int'l Joint Research / Invited
• [Presentation] Spectral flows and surface terminations in higher-order topological insulators (2020)
  • Author(s): 村上修一
  • Organizer: Recent Developments on Multipole Moments in Quantum Systems
  • Int'l Joint Research / Invited
• [Presentation] Axion insulators and topological chiral hinge states protected by inversion symmetry (2020)
  • Author(s): 村上修一
  • Organizer: CORRELATED ELECTRONS VIRTUAL INTERNATIONAL SEMINARS (CEVIS)
  • Int'l Joint Research / Invited
• [Presentation] Theoretical approaches to topological materials (2020)
  • Author(s): 村上修一
  • Organizer: CEMS colloquium
  • Int'l Joint Research / Invited
• [Presentation] Topological materials and higher-order topological materials (2020)
  • Author(s): 村上修一
  • Organizer: 2nd IIT Guwahati and TokyoTech Joint Workshop onCondensed Matter and High Energy Physics
  • Int'l Joint Research / Invited
• [Presentation] Generations and conversions of phonon angular momenta (2020)
  • Author(s): Shuichi Murakami
  • Organizer: New Perspective in Spin Conversion Science
  • Int'l Joint Research / Invited
• [Presentation] Higher-order topological crystalline insulating phase in topological electride apatite (2020)
  • Author(s): Shuichi Murakami
  • Organizer: The 2nd Annual symposium in the Tokyo Tech-UCL-McGill Core-to-Core collaboration Defect Functionalized Sustainable Energy Materials:From Design to Devices Application
  • Int'l Joint Research / Invited
• [Presentation] Spectral flows and surface terminations in higher-order topological insulators (2020)
  • Author(s): Shuichi Murakami
  • Organizer: Recent Developments on Multipole Moments in Quantum Systems
  • Int'l Joint Research / Invited
• [Presentation] Bloch Band Theory for Non-Hermitian Systems (2019)
  • Author(s): Shuichi Murakami
  • Organizer: NTTI2019 and BEC 2019
  • Int'l Joint Research / Invited
• [Presentation] New Horizons of Topological Material Science (2019)
  • Author(s): Shuichi Murakami
  • Organizer: SSDM 2019
  • Int'l Joint Research / Invited
• [Presentation] Theory of generation and conversion of phonon angular momenta (2019)
  • Author(s): Shuichi Murakami
  • Organizer: SpinPeru
  • Int'l Joint Research / Invited
• [Presentation] New Horizons of Topological Material Science (2019)
  • Author(s): Shuichi Murakami
  • Organizer: TokyoTech and IIT Guwahati Joint Workshop Condensed Matter and High-Energy Physics
  • Int'l Joint Research / Invited
• [Presentation] Anomalous dielectric response in insulators with the pi Zak phase (2019)
  • Author(s): Shuichi Murakami
  • Organizer: Materials Research Meeting 2019
  • Int'l Joint Research
• [Presentation] トポロジカル材料科学の現状と展開 (2019)
  • Author(s): 村上修一
  • Organizer: 第７３回 超精密加工専門委員会 研究会 「量子力学の世界が織りなす物理の深淵とその応用」
  • Invited
• [Presentation] Topological phases in condensed matter (2019)
  • Author(s): Shuichi Murakami
  • Organizer: Tokyo Institute of Technology and Stony Brook University Joint Science and Technology Meeting (TokyoTech-SBU meeting 2019)
  • Int'l Joint Research / Invited
• [Presentation] Bloch Band Theory for Non-Hermitian Systems (2019)
  • Author(s): Shuichi Murakami
  • Organizer: New Trends in Topological Insulators 2019 and Variety and Universality of Bulk-Edge Correspondence in Topological Phases 2019
  • Int'l Joint Research / Invited
• [Presentation] New Horizons of Topological Material Science (2019)
  • Author(s): Shuichi Murakami
  • Organizer: SSDM2019 (2019 Internatinoal Conference on Solid State Devices and Materials)
  • Int'l Joint Research / Invited
• [Presentation] New routes to topological materials (2019)
  • Author(s): Shuichi Murakami
  • Organizer: The 380th ZhongGuanCun Forum
  • Int'l Joint Research / Invited
• [Presentation] Anomalous dielectric response in insulators with the p Zak phase (2019)
  • Author(s): Shuichi Murakami
  • Organizer: Materials Research Meeting 2019
  • Int'l Joint Research
• [Presentation] Electrides as a New Platform of Topological Materials (2019)
  • Author(s): M. Hirayama, S. Matsuishi, H. Hosono, and S. Murakami
  • Organizer: APS March Meeting 2019
  • Int'l Joint Research
• [Presentation] トポロジカル物質の新たな舞台としての電子化物 (2019)
  • Author(s): 平山元昭，松石聡，細野秀雄，村上修一
  • Organizer: 日本物理学会 第74回年次大会
• [Presentation] 第一原理手法を用いたトポロジカル系の理論研究と材料提案 (2019)
  • Author(s): 平山元昭
  • Organizer: 日本物理学会 第74回年次大会
  • Invited
• [Presentation] 第一原理計算によるトポロジカル材料開拓 (2018)
  • Author(s): 平山元昭
  • Organizer: 元素戦略研究センターセミナー
  • Invited
• [Presentation] 第一原理計算による新しいトポロジカル半金属相の開拓 (2018)
  • Author(s): 平山元昭
  • Organizer: 日本物理学会2018年秋季大会
  • Invited
• [Presentation] 対称性の観点からの第一原理トポロジカル物質探索 (2018)
  • Author(s): 平山元昭
  • Organizer: 物質のトポロジカル相の理論的探究