Search for quantum skyrmions

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K21839
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Tohoku University
• Principal Investigator: Sato Taku 東北大学, 多元物質科学研究所, 教授 (70354214)
• Project Period (FY): 2019-06-28 – 2023-03-31
• Keywords: quantm skyrmion / neutron scattering / high energy resolution / inelastic scattering

Outline of Final Research Achievements

Skyrmions are originally proposed as topological defects in a continuum field. Magnetic skyrmions, skyrmion-like defects in magnetization field, were observed as spin textures in the chiral magnet MnSi in 2009, and have become a central issue in condensed matter physics. Because of inherent topological protection of the magnetic skyrmions, they have attracted wide attention and been intensively studied from fundamental physics viewpoint to technological application as information carriers. In this study, we proposed to search for quantum skyrmions. We have systematically synthesized a large number of materials, mainly itinerant quantum magnets including Ce3+ and Yb3+, and measured their bulk magnetism and neutron scattering. As a representative result, we found a triple-q structure in a hexagonal Yb intermetallic compound near absolute zero temperature. We have also obtained various other results.

Free Research Field

磁性・中性子散乱

Academic Significance and Societal Importance of the Research Achievements

磁気スカーミオンは磁性物理学からデバイス応用までの広い観点から精力的に研究されている。当初磁気スカーミオンは反転対称性の破れた系で観測されてきたが、最近では反転対称な系でも観測されるなどますます普遍的に見られている。一方で、それらのほとんどは有限温度で観測される熱揺らぎ起源と考えられている。本研究で我々が発見した絶対零度近傍での triple-q 構造形成は、過去に観測された例が少なく新規なものと考えられる上に、これまで知られている熱揺らぎ起源の磁気スカーミオンとは本質的に異なる可能性があり、この発見の学術的意義は大きいと考えられる。