Quantum phase and inelastic neutron scattering

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K03727
• 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: High Energy Accelerator Research Organization
• Principal Investigator: Itoh Shinichi 大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 教授 (00221771)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 金属磁性 / ベリー位相 / スピンカイラリティー / スピンダイナミクス / 磁気励起 / 中性子非弾性散乱

Outline of Final Research Achievements

In ferromagnets where exchange-split bands cross each other by spin-orbit interaction, the band crossing gives rise to the Berry phase, which is the origin of the anomalous Hall effect. It was shown that the temperature dependence of the spin-wave dispersion relation in SrRuO3, where the anomalous Hall effect can be explained by this mechanism, corresponds to a temperature dependence of the Berry curvature. In this study, it is found that the spin-wave dispersion relations of the metallic ferromagnet Nd2Mo2O7 and the metallic antiferromagnet Mn3Sn, where the anomalous Hall effect can be explained by spin chirality, show the same behavior as that of SrRuO3, and it is universally shown that the Berry curvature is an observable quantity in inelastic neutron scattering. We also revealed the spin dynamics of metallic antiferromagnets throughout the entire Brillouin zone.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

物性物理学の中心的課題は、多体電子系における電子のもつ複数の物理自由度（スピン、軌道、電荷）と結晶格子との相互作用、及び、電子間の相関効果による新奇な物性の発現の探査とその発現機構の解明にある。中性子非弾性散乱は、従来から、電子のこれら物理自由度を検出するためのプローブとして貢献してきた。本研究では、物理自由度の競合の結果生じる量子位相が中性子非弾性散乱の観測量であることを新たに示し、中性子非弾性散乱が物性物理学の解明に寄与できる新しいチャンネルを持つことを示したものである。