Study of the phase diagram of nickelate superconductors by a combination of the first-principle calculation and methods for strongly correlated electron systems

• Project/Area Number: 20K22342
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Kitatani Motoharu 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, 基礎科学特別研究員 (50871331)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 超伝導 / 強相関電子系 / 第一原理計算 / 動的平均場理論 / 高温超伝導 / 強相関

Outline of Research at the Start

ニッケル酸化物における超伝導は、銅酸化物・鉄系化合物に続く新たな高温超伝導物質群を形成することが期待され、固体物性の分野で現在最も注目されている物質である。本研究では、第一原理計算と電子相関を正確に取り扱える多体手法を組み合わせた最新の理論を用いて、ニッケル酸化物超伝導体における相図の全貌を明らかにする。

Outline of Final Research Achievements

There are many discussions about various phases due to multiple mechanisms in unconventional superconductors, typical examples of correlated electron systems. In this study, we evaluated the phase diagram of the recently discovered infinite-layer nickelate superconductor, considering the charge transfer due to the multi-orbital nature. We have also extended our method to multi-orbital systems. We explained the transition temperature quantitatively also for the newly discovered five-layer nickelate superconductor.

Academic Significance and Societal Importance of the Research Achievements

強相関電子系において定量的な物性計算を可能とすることは、物質依存性の理解・ひいては機能の向上を目指すための基盤となり得る。その意味で今回ニッケル酸化物において実験と定量的に整合する転移温度が得られたことは意義が大きい。また、５層系のニッケル酸化物の計算においては、強相関効果による電荷の移動が超伝導発現に影響を与えていることが示され、本研究で行った第一原理計算と強相関手法の組み合わせの重要性を確認することが出来た。

Research Products

• [Int'l Joint Research] Vienna University of Technology(オーストリア)
• [Int'l Joint Research] Northwest University(中国)
• [Int'l Joint Research] IFW Dresden(ドイツ)
• [Int'l Joint Research] NIMTE(中国)
• [Int'l Joint Research] ウイーン工科大学(オーストリア)
• [Journal Article] Hidden, one-dimensional, strongly nested, and almost half-filled Fermi surface in Ba2CuO3+y superconductors (2022)
  • Author(s): Worm Paul、Kitatani Motoharu、Tomczak Jan M.、Si Liang、Held Karsten
  • Journal Title: Physical Review B Volume: 105 Issue: 8 Pages: 085110-085110
  • DOI: 10.1103/physrevb.105.085110
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Phase Diagram of Nickelate Superconductors Calculated by Dynamical Vertex Approximation (2022)
  • Author(s): Held Karsten、Si Liang、Worm Paul、Janson Oleg、Arita Ryotaro、Zhong Zhicheng、Tomczak Jan M.、Kitatani Motoharu
  • Journal Title: Frontiers in Physics Volume: 9 Pages: 810394-810394
  • DOI: 10.3389/fphy.2021.810394
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Natural orbital impurity solver for real-frequency properties at finite temperature (2021)
  • Author(s): Motoharu Kitatani, Shiro Sakai, Ryotaro Arita
  • Organizer: APW-RIKEN-Tsinghua-Kavli workshop “Highlights on condensed matter physics”
  • Int'l Joint Research
• [Presentation] Calculation of the phase diagram of nickelate superconductors (2021)
  • Author(s): Motoharu Kitatani, Liang Si, Oleg Janson, Zhicheng Zhong, Paul Worm, Jan M. Tomczak, Ryotaro Arita, Karsten Held
  • Organizer: APS March Meeting
  • Int'l Joint Research