Probing quantum critical phenomena driven by diverse order parameter via complementary use of quantum beams

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05031
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Quantum beam science
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Kaneko Koji 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 物質科学研究センター, 研究主幹 (30370381)
• Project Period (FY): 2016-10-21 – 2020-03-31
• Keywords: 中性子散乱 / 放射光 / 強相関物性 / 量子臨界現象 / 磁気スキルミオン

Outline of Final Research Achievements

Various order parameters, such as magnetism and lattice, and their coupling can give rise to novel quantum phenomena in the vicinity of a critical point. In this study, neutron and synchrotron x-ray were complementary used to get microscopic insights into these novel phenomena. In YbRh2Si2, prototypical compound showing a magnetic driven quantum critical point (QCP), new type of magnetic order parameter was revealed in the slightly Co doped sample near QCP. In (Ca,Sr)3T4Sn13, non-magnetic lattice driven QCP was evidenced by phonon spectroscopies. And EuPtSi, a formation of magnetic skyrmion lattice in f-electron compound is identified near the critical region under magnetic fields, and its unique characteristics such as short periodicity and magnetic anisotropy were revealed. In overall, new type of static and dynamical responses were characterized near the critical point.

Free Research Field

中性子散乱，放射光散乱，固体物理

Academic Significance and Societal Importance of the Research Achievements

本課題では，中性子と放射光X線，各々の特徴を活かし，磁性や格子により引き起こされる臨界点近傍の特徴的な振る舞いを微視的に明らかにした．これらの情報は，量子ビームプローブでのみ得られるもので，他の実験結果や理論的な研究の進展に有益な成果が得られた．また実験は，J-PARCやSPring-8などの大型施設を相補的に駆使して実施したもので，先端施設の有用性を示す意味でも有意義な成果であったと言える．