Development of the dHvA experiment under pressure using constant load system and Fermi surface study for strongly correlated electron system

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K03713
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Niigata University
• Principal Investigator: Settai Rikio 新潟大学, 自然科学系, 教授 (00251041)
• Co-Investigator(Kenkyū-buntansha): 上床 美也 東京大学, 物性研究所, 教授 (40213524)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 純良単結晶育成 / 高圧実験 / ドハース・ファンアルフェン効果 / フェルミ面

Outline of Final Research Achievements

We have developed pressure cells for observing de Haas-van Alphen (dHvA) and Shubnikov-Dohaas (SdH) oscillations under pressure using a constant-load pressure apparatus and grown single crystals of strongly correlated electron systems containing rare earth and transition metal elements to investigate their electronic and magnetic states from experiments on electrical resistance, specific heat, magnetization and dHvA (SdH) oscillation experiments. In the heavy-fermion CeIrIn5 and CeRhIn5, the electronic states around metamagnetic and/or the Lifshitz transition were investigated. Experiments on the dHvA effect in the heavy-fermion ferromagnet CeRh6Ge4 and reference materials revealed that the 4f electrons in Ce are itinerant rather than localized electrons as thought in previous studies.

Free Research Field

物性物理学（強相関電子系，磁性，超伝導）

Academic Significance and Societal Importance of the Research Achievements

希土類元素や遷移金属元素が有するf電子やd電子は，他のs電子やp電子を媒介として，強い磁性や超伝導といった学術的に興味深い物性を引き起こす。また，半導体的，絶縁体的な性質を示す場合も，f電子やd電子は重要な働きを示す。このような物質の本質的な電子状態を明らかにするためには，純良な単結晶を用いた圧力実験と強磁場実験が重要な役割を果たす。本研究では，圧力下のdHvA実験の適用範囲を広げるための圧力装置の開発を行うとともに，純良な単結晶，新物質の単結晶育成に成功した。これは強相関電子系の研究を推進する上で，学術的に意義の高い研究であると言える。