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Nobukane Hiroyoshi

Faculty of Science　Physics　Electronic Condensed Matter PhysicsAssistant Professor

Researcher basic information

■ Degree
  • 博士（工学）, 北海道大学
■ URL
researchmap URLホームページURL■ Various IDs
Researcher number
  • 60550663
J-Global ID■ Research Keywords and Fields
Research Keyword
  • 電荷・スピン密度波
  • カイラリティ
  • トポロジー
  • 超伝導
Research Field
  • Natural Science, Magnetism, superconductivity and strongly correlated systems
■ Educational Organization

Career

■ Career
Career
  • Oct. 2010 - Present
    Hokkaido University, Faculty of Science, Department of Physics, 助教
  • Apr. 2009 - Sep. 2010
    Asahikawa Medical University, School of Medicine, 助教
  • 2007 - 2009
    日本学術振興会 特別研究員（DC1）
Committee Memberships
  • Apr. 2022 - Mar. 2023
    日本物理学会領域6 運営委員

Research activity information

■ Papers
■ Other Activities and Achievements
■ Lectures, oral presentations, etc.
  • High-Tc superconductivity in 2D ruthenates: Relation to charge and spin deisity wave
    Hiroyoshi Nobukane
    ECRYS 2022, Aug. 2022, English, Invited oral presentation
    [Invited]
  • Superconductor-insulator transition in a two-dimensional ruthenate
    延兼 啓純
    Localisation 2022, Aug. 2022, English, Oral presentation
  • Co-appearance of high-Tc superconductivity and ferromagnetism in Ca2RuO4 nanocrystals
    Hiroyoshi Nobukane
    APS 2021, Mar. 2021, English, Oral presentation
  • Observation of two dimensional high-Tc superconductivity in a Ca2RuO4 nanofilm single crystal
    Hiroyoshi Nobukane
    APS 2018, Mar. 2018, English, Oral presentation
  • Observation of two dimensional high-Tc superconductivity in a Ca2RuO4 nanofilm
    Hiroyoshi Nobukane
    Topological Matter and Flat Bands Conference 2017, Aug. 2017, English, Oral presentation
  • Chern structure in Sr2RuO4 thin films
    Hiroyoshi Nobukane
    Materials & Mechanisms of Superconductivity (M2S) 2015, Aug. 2015, English, Oral presentation
  • Topological electromagnetic response in the chiral superconductors Sr2RuO4
    Hiroyoshi Nobukane
    ECRYS-2014, Aug. 2014, English, Invited oral presentation
    [Invited]
  • Parity violation in a chiral single domain Sr2RuO4 Implication of Majorana fermions
    Hiroyoshi Nobukane
    I. F. Schegolev Memorial Conference "Low-Dimensional Metallic and Superconducting Systems, Oct. 2009, English, Invited oral presentation
    [Invited]
■ Syllabus
  • 物理学実験Ⅰ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅰ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅱ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅱ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅲ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅳ, 2024年, 学士課程, 理学部
  • 物理学実験Ⅳ, 2024年, 学士課程, 理学部
■ Affiliated academic society
  • American Physical Society
  • THE PHYSICAL SOCIETY OF JAPAN
■ Research Themes
  • Quantum anomaly and topology in layered ruthenates
    Grants-in-Aid for Scientific Research
    2017 - 2019
    Nobukane Hiroyoshi
    We report the observation of a Chern structure in the Bose-insulating phase of Sr2RuO4 nanofilms by employing electric transport. Fractional quantized conductance was observed without an external magnetic field. We found an anomalous induced voltage with temperature and thickness dependence, and the induced voltage exhibited switching behavior when we applied a magnetic field. We suggest that there was fractional magnetic-field-induced electric polarization in the interlayer.
    We report the realization of high-temperature superconductivity in Ca2RuO4 nanofilm single crystals. A Ca2RuO4 thin-film exhibits zero resistance and typical Berezinskii-Kosterlitz-Thouless transition behavior where the highest onset temperature 96 K is observed in electric transport measurements. We also found that the induced bias current and the tuned film thickness cause a superconductor-insulator transition.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 17K14326
  • Paramagnetic Meissner effect in topological superconductors
    Grants-in-Aid for Scientific Research
    Apr. 2014 - Mar. 2017
    ASANO Yasuhiro; AMITSUKA Hiroshi
    The diamagnetism is a essential property of all superconductors. However, the paramagnetic response has been observed in a number of small superconductors. The mechanism and basic physical picture of the paramagnetic response has been an open question. In this project, we make clear (1) odd-frequency Cooper pairs appear at a surface of a topological superconductor, (2) odd-frequency Cooper pairs are paramagnetic, (3) therefore odd-frequency Cooper pairs are responsible for the paramagnetic response of a small topological superconductor at low temperature.
    Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Competitive research funding, 26287069
  • Development of Angle-resolved STM Spectroscopy on Organic Superconductors with use of FIB processing
    Grants-in-Aid for Scientific Research
    2013 - 2015
    Nomura Kazushige; NOBUKANE Hiroyoshi
    In order to determine the symmetry of superconducting gap in the system of the organic superconductors without the cleavage, we developed the method to carry out the angle-resolved STM spectroscopy measurement obtaining the specified crystal surface of single crystal with the FIB processing. We found from the STM observation that the processed surface for the angle-resolved STM spectroscopy should have the surface index with small integers, and established the coverage of this method. In addition, we found that the node direction of the d-wave superconductivity changes with the increase of electron correlation in the organic superconductor system, and obtained the new knowledge for the mechanism of superconductivity.
    Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Coinvestigator not use grants, Competitive research funding, 25610083
  • Topological invariant in chiral superconductors
    Grants-in-Aid for Scientific Research
    2013 - 2015
    Nobukane Hiroyoshi
    We report the topological invariant in Sr2RuO4 nanoscale single crystals by measuring the electric transport properties. We observed the parity violation of current-voltage curves due to the excitation of the Majorana-Wyle fermions along the one-dimensional chiral edge current of single domain Sr2RuO4. In the absence of an external magnetic field, the two-dimensional surface transport in Sr2RuO4 thin films exhibited a fractional quantum Hall conductance in the superconducting state. The fractional magnetic-field-induced electric polarization was observed under zero bias current as the three-dimensional interlayer conduction. The fractional axion angle θ=π/6 is determined by observing the topological magneto-electric effect in Sr2RuO4 nanocrystals.
    Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 25800183
  • Search of novel quantum transport phenomena in a single domain of chiral superconductors
    Grants-in-Aid for Scientific Research(若手研究(スタートアップ), 研究活動スタート支援)
    2009 - 2011
    Hiroyoshi NOBUKANE
    We found the parity-violating curves in a single domain of Sr_2RuO_4 superconductors through electric transport measurements. The results show that the Sr_2RuO_4 itself provides spontaneous magnetization. An applied magnetic field changes the chirality of the single domain. We suggest that the Majorana fermions are excited at the edge of Sr_2RuO_4.
    Ministry of Education, Culture, Sports, Science and Technology, 若手研究(スタートアップ), 研究活動スタート支援, 旭川医科大学->北海道大学, Principal investigator, Competitive research funding, 21840004
  • 大局的トポロジー構造におけるトポロジカルソリトンの生成・消滅過程の研究
    特別研究員奨励費
    2006 - 2008
    延兼啓純
    本年度はSU(2)ゲージ対称性を持つカイラルp波超伝導体Sr2RuO4に対して、T=0.1K以下の状況下においてc軸に平行に磁場を印加し、H>Hc2からH=0へ磁場クエンチ測定を行った。その結果は、量子相転移領域においてべき関数になることを明らかにした。SU(2)超伝導体はU(1)超伝導体では形成されないテクスチャー構造を持つトポロジカル欠陥が期待され初期宇宙の相転移の臨界指数を決定できる可能性がある。この結果を25th international conference on Low Temperature Physicsにて発表した。また一方で、ミリスケールのSr2RuO4はカイラルドメイン構造を持つと考えられるのでシングルドメインサイズの特性を知ることが重要となる。したがって我々はマイクロスケールのSr2RuO4を作成・分析を行い、このサンプルに対して電子ビームリソグラフィを用いて金電極を取り付けた。極低温(〜0.1K)にて電流-電圧特性を測定した。その結果は、バイアス電流に対して偶関数の新奇な電圧の発生を発見した(すなわちV(+I)=V(-I))。これは、パリティが破れている電流-電圧特性であることを意味する。この測定結果を論文にまとめSolid State Communicationsに投稿中であり、より発展したデータを掲載した論文を投稿準備中である。またサンプル電極作製に関する技術的な内容をJournal of Vacuum Science and Technology Bに投稿中である。2008年8月には、ウプサラ大学にてProf.A.J.Niemi,Prof.E.Babaevと、またヘルシンキ工科大学にてProf.G.E.Volovik,Prof.P.Hakonenとそれぞれ実験結果について議論を行った。
    文部科学省, 特別研究員奨励費, 北海道大学, Principal investigator, Competitive research funding, 06J54012