• 研究課題をさがす
  • 研究者をさがす
  • KAKENの使い方
  1. 課題ページに戻る

2019 年度 実施状況報告書

カーボン超原子への内外双方向ドーピングによる新規高温超伝導体の創成

研究課題

研究課題/領域番号 18K18724
研究機関大阪府立大学

研究代表者

プラシデス コスマス  大阪府立大学, 工学(系)研究科(研究院), 教授 (90719006)

研究期間 (年度) 2018-06-29 – 2021-03-31
キーワードSuperconductivity / Molecular nanocarbons / Endohedral fullerene / Dual doping / Magnetism
研究実績の概要

Most superconductors have simple structures built from atoms, but superconductors made from molecules arranged in solid structures also exist. Prominent examples are those of nanocarbon superatoms, the fullerenes (C60) - they show the highest superconducting transition temperature, Tc (38 K) and do not lose their zero resistance performance even under extremely high magnetic fields (>90 Tesla). However, they have now reached their upper limit of performance. In this research, we are attempting to remove this roadblock by using a new building block for molecular superconductors beyond the C60 nanocarbon molecule. This is [Li@C60], an endohedral metallofullerene, which incorporates a Li+ ion inside the C60- cage. We have now developed a scalable method to obtain neutral Li+@C60(-) by chemical reduction of Li+@C60 using decamethylferrocene. The preparative route does not demand long reaction times unlike electrolytic reduction routes. Investigation of solid [Li@C60] revealed the presence mainly of dimers (Li@C60)2, together with the co-existence of a small fraction of the EPR-active monomer form. These results added pieces of important information on the chemistry of the endohedral metal fulleride [Li@C60] as an emerging metal/carbon hybrid. Scalability of this method is of paramount importance and will accelerate research on pristine [Li@C60] in both molecular electronics (solution-processable n-dopant component) and molecular superconductivity/magnetism applications.

現在までの達成度 (区分)
現在までの達成度 (区分)

1: 当初の計画以上に進展している

理由

Superconductors have no electrical resistance and carry electricity without losing energy. The development of new materials in order to achieve transition temperatures to zero-resistance as high as possible is at the extreme forefront of current challenges in materials science. C60 superconductors played leading role in materials research in the last 30 years achieving a robust zero-resistance state at record temperatures and surviving at extremely high magnetic fields. But they have reached their upper limit. Here we are facing the challenge of surpassing the past performance of C60 superconductors. We are targeting to achieve this by developing the uncharted field of high-symmetry superatomic carbon frameworks with metal ions inside the cages and using unprecedented mechanisms of electronic control by dual-direction internal and external electron doping. This is a challenging proposal because there are simply no systems of this type created before and, if and when made, theory predicts superb performance. Currently we have achieved the first milestone of producing and characterizing in the bulk the parent neutral lithium endohedral C60 fullerene - this constitutes the starting material, the synthon of our eventual targets and confirms that we are progressing at an excellent pace for this research.

今後の研究の推進方策

Our research plan follows two complementary procedures: (i) to develop the new synthetic chemistry needed, and (ii) to combine it with advanced structural and physical property measurements and feedback from theory. The research will include: [1] Synthesis of dual-direction-doped A+n[Li+@C60(n+1)-] phases (A = alkali metal; n = 1-6). This will define the full range of valences and electronic ground states in C60 cages dually-electron-doped internally and externally. [2] Physical control of structure and properties. Application of pressure will be used to drive insulator-to-metal transitions and trigger the emergence of superconductivity out of non-superconducting A+n[Li+@C60(n+1)-] precursors away from half filling of the conduction band. [3] Electronic and magnetic ground states in the new materials. The strong interplay between crystal and electronic structure requires the use of many advanced experimental techniques at both ambient and elevated pressures. We have the expertise to employ the full range of experimental techniques to investigate crystal structure (synchrotron X-ray & neutron diffraction), electronic
structure (magnetometry, transport properties, specific heat) and dynamics (NMR/muSR/EPR & IR/Raman spectroscopy) throughout the project duration. The integrated study of structure and electronic properties in the normal and superconducting states will be the basis for theoretical understanding of the new metallic/superconducting ground states.

次年度使用額が生じた理由

The research started after the beginning of the financial year 2018 and in this period to-date utilized pre-existing resources in the applicant's laboratory. Moreover, the emphasis of the project was initially (as described originally in the proposal) to isolate and purify (Li@C60)2. This was achieved by optimizing the bulk synthesis and purification of the neutral (Li@C60)2 dimer from the monomeric ionic precursor, (Li@C60)(PF6) targeting the availability of the material in large-quantities to allow full exploratory synthesis. This part of the work has been successful and was achieved with resources well within our budget. The next steps involve more elaborate physical characterization as a function of temperature as well as the utilization of high pressure to enhance the properties. This will require significant resources including those carried over.

  • 研究成果

    (23件)

すべて 2020 2019 その他

すべて 国際共同研究 (6件) 雑誌論文 (3件) (うち国際共著 3件、 査読あり 3件) 学会発表 (12件) (うち国際学会 5件、 招待講演 6件) 図書 (1件) 備考 (1件)

  • [国際共同研究] University of Liverpool/Rutherford Appleton Laboratory(英国)

    • 国名
      英国
    • 外国機関名
      University of Liverpool/Rutherford Appleton Laboratory
  • [国際共同研究] Aristotle University of Thessaloniki(ギリシャ)

    • 国名
      ギリシャ
    • 外国機関名
      Aristotle University of Thessaloniki
  • [国際共同研究] Bursa Technical University(トルコ)

    • 国名
      トルコ
    • 外国機関名
      Bursa Technical University
  • [国際共同研究] NIST(米国)

    • 国名
      米国
    • 外国機関名
      NIST
  • [国際共同研究] Charles University(チェコ)

    • 国名
      チェコ
    • 外国機関名
      Charles University
  • [国際共同研究]

    • 他の国数
      1
  • [雑誌論文] Pressure-Induced Charge Disorder-Order Transition in the Cs4O6 Sesquioxide2020

    • 著者名/発表者名
      Okur H. Esma、Colman Ross H.、Ohishi Yasuo、Sans Annette、Felser Claudia、Jansen Martin、Prassides Kosmas
    • 雑誌名

      Inorganic Chemistry

      巻: 59 ページ: 1256~1264

    • DOI

      10.1021/acs.inorgchem.9b02974

    • 査読あり / 国際共著
  • [雑誌論文] Chemical reduction of Li+@C60 by decamethylferrocene to produce neutral Li+@C60-2019

    • 著者名/発表者名
      Okada Hiroshi、Ueno Hiroshi、Takabayashi Yasuhiro、Nakagawa Takeshi、Vrankic Martina、Arvanitidis John、Kusamoto Tetsuro、Prassides Kosmas、Matsuo Yutaka
    • 雑誌名

      Carbon

      巻: 153 ページ: 467~471

    • DOI

      10.1016/j.carbon.2019.07.028

    • 査読あり / 国際共著
  • [雑誌論文] Elusive Valence Transition in Mixed-Valence Sesquioxide Cs4O62019

    • 著者名/発表者名
      Colman Ross H.、Okur H. Esma、Kockelmann Winfried、Brown Craig M.、Sans Annette、Felser Claudia、Jansen Martin、Prassides Kosmas
    • 雑誌名

      Inorganic Chemistry

      巻: 58 ページ: 14532~14541

    • DOI

      10.1021/acs.inorgchem.9b02122

    • 査読あり / 国際共著
  • [学会発表] Materials development in π-f electron systems2020

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The 2019 J-Physics Annual Meeting (Kobe)
    • 招待講演
  • [学会発表] Pressure-induced valence transitions in mixed valence rare-earth fullerides2020

    • 著者名/発表者名
      Keisuke Matsui, Kosmas Prassides
    • 学会等名
      The 2020 JPS Annual Meeting (Nagoya)
  • [学会発表] Quantum magnetism in fully-frustrated all-carbon π-electron systems2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      International Workshop on Phase Transition and Dynamical Properties of Spin Transition Materials (PDSTM 2019) (Gainesville, Florida, USA)
    • 国際学会 / 招待講演
  • [学会発表] Emergent Electronic Phenomena in All-Carbon π-Electron Molecular Systems2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The 1st Nanjing Conference on Quantum Materials (NCQM-2019) (Nanjing, China)
    • 国際学会 / 招待講演
  • [学会発表] Emergent electronic phenomena in mixed valence rare-earth fullerides2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The International Conference on Quantum Physics in Complex Matter: Superconductivity, Magnetism and Ferroelectricity, Superstripes 2019 (Ischia, Naples, Italy)
    • 国際学会 / 招待講演
  • [学会発表] Emergent electronic phenomena in hybrid f-/p- electron molecular materials2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The J-Physics 2019 International Conference & KINKEN-WAKATE 2019 Multipole Physics (Kobe)
    • 国際学会
  • [学会発表] Emergent electronic phenomena in mixed valence rare-earth fullerides2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The International Conference on Electron Correlation in Superconductors and Nanostructures (ECSN-2019) (Odessa, Ukraine)
    • 国際学会 / 招待講演
  • [学会発表] Metal-directed asymmetric spatial assembly of diverse building blocks - spheres, planes, and bowls2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The 2019 Coordination Asymmetry Annual Meeting (Tokyo)
  • [学会発表] Emergent electronic phenomena in intermediate valence rare-earth fullerides2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The J-Physics Mini-Workshop in Osaka (Osaka)
  • [学会発表] Mixed valence transitions in rare-earth fullerides2019

    • 著者名/発表者名
      Naoya Yoshikane, Kosmas Prassides
    • 学会等名
      The 2019 Autumn Meeting, The Physical Society of Japan (Gifu)
  • [学会発表] Tuning of mixed valency in asymmetrically- coordinated rare-earth fullerides2019

    • 著者名/発表者名
      Naoya Yoshikane, Kosmas Prassides
    • 学会等名
      The 69th Conference of the Japan Society of Coordination Chemistry (Nagoya)
  • [学会発表] Superconductivity and quantum magnetism in p-electron systems: a personal ongoing voyage into the unexpected2019

    • 著者名/発表者名
      Kosmas Prassides
    • 学会等名
      The 407th colloquium of the Solid State Physics Seminars Series, Department of Applied Physics, School of Engineering, Nagoya University
    • 招待講演
  • [図書] Superconductivity: From Materials Science to Practical Applications2019

    • 著者名/発表者名
      P. Mele, K. Prassides, C. Tarantini, A. Palau, P. Badica, A. K. Jha, T. Endo
    • 総ページ数
      379
    • 出版者
      Springer Nature
  • [備考] Electronic Functional Materials Laboratory

    • URL

      http://mtr1.osakafu-u.ac.jp/prassides-lab/

URL: 

公開日: 2021-01-27  

サービス概要 検索マニュアル よくある質問 お知らせ 利用規程 科研費による研究の帰属

Powered by NII kakenhi