Gapless spin liquid in a square-kagome lattice antiferromagnet
Gapless spin liquid in a square-kagome lattice antiferromagnet
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DOI：
10.1038/s41467-020-17235-z
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发表时间：
2020-07-09
影响因子：
16.6
通讯作者：
Nakajima, Kenji
中科院分区：
文献类型：
--
作者：
Fujihala, Masayoshi;Morita, Katsuhiro;Nakajima, Kenji
量子自旋液体（QSL）状态的观测是凝聚态物理学中最重要的目标之一，也是支持下一代工业的新型自旋电子器件的开发。二维量子自旋系统中的QSL被认为是由于几何磁阻挫，因此基于kagome的晶格是QSL最可能的运动场。本文报道了KCu_6AlBiO_4（SO_4）（5）Cl量子反铁磁体QSL态的首次实验结果。通过磁化率，磁化强度，热容量，μ子自旋弛豫（μ SR），和非弹性中子散射（INS）测量的综合实验研究揭示了在非常低的温度接近基态的无隙QSL的形成。QSL的行为不能完全用最近邻交换相互作用的受挫海森堡模型来解释，这为揭示QSL状态的本质提供了理论挑战。
Observation of a quantum spin liquid (QSL) state is one of the most important goals in condensed-matter physics, as well as the development of new spintronic devices that support next-generation industries. The QSL in two dimensional quantum spin systems is expected to be due to geometrical magnetic frustration, and thus a kagome-based lattice is the most probable playground for QSL. Here, we report the first experimental results of the QSL state on a square-kagome quantum antiferromagnet, KCu6AlBiO4(SO4)(5)Cl. Comprehensive experimental studies via magnetic susceptibility, magnetisation, heat capacity, muon spin relaxation (mu SR), and inelastic neutron scattering (INS) measurements reveal the formation of a gapless QSL at very low temperatures close to the ground state. The QSL behavior cannot be explained fully by a frustrated Heisenberg model with nearest-neighbor exchange interactions, providing a theoretical challenge to unveil the nature of the QSL state.