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

2021 Fiscal Year Final Research Report

• 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
• Keywords: 超伝導 / 強相関電子系 / 第一原理計算 / 動的平均場理論

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.

Free Research Field

物性理論

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。