New frontiers in organic triangular lattice spin liquids

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02709
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: Maesato Mitsuhiko 京都大学, 理学研究科, 准教授 (60324604)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: スピン液体 / モット絶縁体 / 低温電子物性 / デバイス

Outline of Final Research Achievements

When spins are localized on a triangular lattice with antiferromagnetic interactions between neighboring spins, a quantum spin liquid state can be expected in which long-range magnetic ordering is suppressed down to extremely low temperature due to geometrical frustration effects. However, all organic triangular lattice spin liquid candidates discovered so far are accompanied by disorder in their crystal structure, and the effects of frustration and disorder remain unclear.
In this study, we aim to develop organic spin liquids with a triangular lattice free from disordered structure and have succeeded in synthesizing a promising material. We performed various magnetic measurements down to very low temperature and found that the material is a good candidate for a quantum spin liquid. However, it was also found that a small amount of Cu(II) ions were contaminated in the anion layer as magnetic impurities.

Free Research Field

物性物理、物性化学

Academic Significance and Societal Importance of the Research Achievements

幾何学的なフラストレーション効果によって極低温まで長距離の磁気秩序が抑制された量子スピン液体状態は、非自明な量子状態として興味深いだけでなく、量子コンピューターへの応用なども期待され、近年注目を集めている。ところが、実際の物質では構造の乱れの影響が無視できず、フラストレーションと乱れの効果が明確でない。本研究では、陰イオン層の構造の乱れが抑制された新しい有機三角格子系の開発に成功し、乱れの無い量子スピン液体の実現に向けた新たな指針を得ることができた。