Theoretical study aiming to detect and control Majorana quasiparticles in topological superconductors

• Project/Area Number: 16K17755
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Osaka University (2019); Kyoto University (2017-2018); National Institute for Materials Science (2016)
• Principal Investigator: Kawakami Takuto 大阪大学, 理学研究科, 助教 (00750895)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: トポロジカル超伝導 / マヨラナ準粒子励起 / トポロジカル半金属 / 超流動3He / p波超流動 / FFLO状態 / Ginzburg-Landau理論 / マヨラナ準粒子 / 3/2スピン / マヨラナ束縛状態 / 量子渦

Outline of Final Research Achievements

We theoretically investigated superconductivity in topological materials and their Majorana quasiparticle excitation, on the basis of symmetry consideration and numerical solution of the Bogoliubov-de Gennes equation and gap equation. In particular, we pointed out that recently discovered superconducting anti-perovskite material Sr3SnO can be a novel topological superconductor characterized by large winding number. It was also shown that iron-based superconductors can have a variety of Majorana quasiparticles protected by crystalline symmetry, such as Majorana quartet, Majorana flat band, and Moebius surface states. In addition, we studied the nodal line semimetal phase in photonic crystal system.

Academic Significance and Societal Importance of the Research Achievements

逆ペロブスカイト物質や鉄系超伝導などの現在実験が進行中の物質を舞台として，新しいトポロジカル超伝導の出現を指摘したことで，今後のさらなる実験的研究の動機付けとなることが期待される。さらに，本研究で得られた相図や用いた解析手法を応用することで，対象とした物質固有の性質だけでなく，多様なトポロジカル物質を効率よく解析することが可能になった。現在もマヨラナ準粒子を用いた量子コンピューターの実現にむけた研究が盛んに行われているが，本研究もそのさらなる促進に寄与すると期待される。

Research Products

• [Int'l Joint Research] Chinese Academy of Sciences(中国)
• [Int'l Joint Research] Princeton University(米国)
• [Int'l Joint Research] Julius-Maximilians-Universitat Wurzburg(ドイツ)
• [Journal Article] Topological junction states and their crystalline network in systems with chiral symmetry: Application to graphene nanoribbons (2020)
  • Author(s): Tamaki Gen、Kawakami Takuto、Koshino Mikito
  • Journal Title: Physical Review B Volume: 101 Issue: 20 Pages: 2053111-11
  • DOI: 10.1103/physrevb.101.205311
  • Peer Reviewed
• [Journal Article] Topological crystalline superconductivity in Dirac semimetal phase of iron-based superconductors (2019)
  • Author(s): Kawakami Takuto、Sato Masatoshi
  • Journal Title: Physical Review B Volume: 100 Issue: 9
  • DOI: 10.1103/physrevb.100.094520
  • Peer Reviewed
• [Journal Article] Topological Crystalline Materials of J=3/2 Electrons: Antiperovskites, Dirac Points, and High Winding Topological Superconductivity (2018)
  • Author(s): Kawakami Takuto、Okamura Tetsuya、Kobayashi Shingo、Sato Masatoshi
  • Journal Title: Physical Review X Volume: 8 Issue: 4
  • DOI: 10.1103/physrevx.8.041026
  • Peer Reviewed / Open Access
• [Journal Article] Multiple topological states in iron-based superconductors (2018)
  • Author(s): P.Zhang, Z. Wang, X. Wu, K. Yaji, Y. Ishida, Y. Kohama, G. Dai, Y. Sun, C. Bareille1, K. Kuroda, T. Kondo1, K. Okazaki, K. Kindo1, X. Wang, C. Jin, J. Hu, R. Thomale, K. Sumida, S. Wu, K. Miyamoto, T. Okuda, H. Ding, G. D. Gu, T. Tamegai, T. Kawakami, M. Sato, S. Shin
  • Journal Title: Nature Physics Volume: 15 Issue: 1 Pages: 41-47
  • DOI: 10.1038/s41567-018-0280-z
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Symmetry-guaranteed nodal-line semimetals in an fcc lattice (2017)
  • Author(s): Kawakami Takuto、Hu Xiao
  • Journal Title: Physical Review B Volume: 96 Issue: 23 Pages: 1-9
  • DOI: 10.1103/physrevb.96.235307
  • Peer Reviewed
• [Journal Article] トポロジカル超伝導研究の現状と展望 (2017)
  • Author(s): 川上拓人, 胡暁
  • Journal Title: Forum of Superconductivity Science and Technology News Volume: 152 Pages: 3-8
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Topological stability of polka-dot phase in superfluid 3He between parallel plates (2019)
  • Author(s): Takuto Kawakami, Takeshi Mizushima
  • Organizer: International Conference on Topological Materials Science 2019
  • Int'l Joint Research
• [Presentation] 平行平板間の超流動 3He における 2 次元空間変調 (2019)
  • Author(s): 川上拓人, 水島健
  • Organizer: 日本物理学会 2019 年秋季大会
• [Presentation] Topological superconductivity of Dirac semimetal in Fe(Se,Te) (2019)
  • Author(s): Takuto Kawakami, Masatoshi Sato
  • Organizer: Oxide Superspin Workshop 2019
  • Int'l Joint Research
• [Presentation] 逆ペロブスカイト酸化物のスピン3/2トポロジカル超伝導 (2018)
  • Author(s): 川上拓人
  • Organizer: 基研研究会「電子相関が生み出す新規な秩序と超伝導現象:トポロジー, 液晶状態, 動的現象」
  • Invited
• [Presentation] Topological Nodal-Line Semimetals in FCC Photonic Crystals (2018)
  • Author(s): T. Kawakami
  • Organizer: Progress In Electromagnetics Research Symposium (PIERS2018)
  • Int'l Joint Research / Invited
• [Presentation] Higher Winding Topological Superconductivity in Antiperovskite Oxides (2018)
  • Author(s): T. Kawakami
  • Organizer: Oxide Superconducting Spintronics Workshop 2018
  • Int'l Joint Research
• [Presentation] Fe(Se,Te) におけるディラック半金属のトポロジカル超伝導 (2018)
  • Author(s): 川上拓人
  • Organizer: 日本物理学会2018年秋季大会
• [Presentation] Superconductivity in spin 3/2 topological insulators with carrier doping (2018)
  • Author(s): T. Kawakami
  • Organizer: 12th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors
  • Int'l Joint Research
• [Presentation] 面心立方格子系におけるトポロジカルノード線半金属状態 (2017)
  • Author(s): 川上拓人, 胡暁
  • Organizer: 日本物理学会 第72回年次大会
  • Place of Presentation: 大阪大学 (大阪府大阪市)
  • Year and Date: 2017-03-17
• [Presentation] Numerical Study for Searching the Majorana Bound States in Topological Superconductor (2017)
  • Author(s): Takuto Kawakami, Xiao Hu
  • Organizer: The 10th International Conference on Computational Physics
  • Place of Presentation: Macao, China
  • Year and Date: 2017-01-16
  • Int'l Joint Research / Invited
• [Presentation] Spin Textures in the Majorana Bound States (2017)
  • Author(s): Takuto Kawakami
  • Organizer: Majorana States in Condensed Matter Towards Topological Quantum Computation
  • Int'l Joint Research
• [Presentation] Spin Texture of Majorana Bound State in Topological Superconductor (2017)
  • Author(s): Takuto Kawakami
  • Organizer: 14th International Workshop on Magnetism & Superconductivity at the Nanoscale
  • Int'l Joint Research / Invited
• [Presentation] Spin 3/2 superconducting topological insulators (2017)
  • Author(s): Takuto Kawakami
  • Organizer: Novel Quantum States in Condensed Matter 2017
  • Int'l Joint Research
• [Presentation] Spin 3/2 superconducting topological insulators (2017)
  • Author(s): Takuto Kawakami
  • Organizer: CEMS Symposium on Trends in Condensed Matter Physics
  • Int'l Joint Research
• [Presentation] Symmetry-Guaranteed Nodal Line Semimetallic states in fcc structures (2017)
  • Author(s): Takuto Kawakami
  • Organizer: Conference on Topological Quantum Phases and Topological Quantum Computation
  • Int'l Joint Research
• [Presentation] スピン3/2トポロジカル絶縁体の超伝導 (2017)
  • Author(s): 川上 拓人
  • Organizer: 日本物理学会第73回年次大会
• [Presentation] Proposal to Identify the Majorana Bound States by Scanning Tunneling Spectroscopy (2016)
  • Author(s): Takuto Kawakami, Xiao Hu
  • Organizer: EMN Meeting on Quantum and Mesoscopic Physcs
  • Place of Presentation: Port Louis, Mauritius
  • Year and Date: 2016-11-30
  • Int'l Joint Research / Invited
• [Presentation] マヨラナ端状態のスピンテクスチャーと干渉 (2016)
  • Author(s): 川上拓人, 胡暁
  • Organizer: 日本物理学会 2016年秋季大会
  • Place of Presentation: 金沢大学 (石川県金沢市)
  • Year and Date: 2016-09-13
• [Presentation] Proposal to detect the Majorana bound states by spin-polarized spectroscopy (2016)
  • Author(s): Takuto Kawakami, Xiao Hu
  • Organizer: Spectroscopy in Novel Superconductors
  • Place of Presentation: Stuttgart/Ludwigsburg, Germany
  • Year and Date: 2016-06-19
  • Int'l Joint Research