Yao Weiliang, Huang Qing, Xie Tao, Podlesnyak Andrey, Brassington Alexander, Xing Chengkun, Mudiyanselage Ranuri S Dissanayaka, Wang Haozhe, Xie Weiwei, Zhang Shengzhi, Lee Minseong, Zapf Vivien S, Bai Xiaojian, Tennant D Alan, Liu Jian, Zhou Haidong
Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2023 Oct 6;131(14):146701. doi: 10.1103/PhysRevLett.131.146701.
Continuous spin excitations are widely recognized as one of the hallmarks of novel spin states in quantum magnets, such as quantum spin liquids (QSLs). Here, we report the observation of such kind of excitations in K_{2}Ni_{2}(SO_{4}){3}, which consists of two sets of intersected spin-1 (Ni^{2+}) trillium lattices. Our inelastic neutron scattering measurement on single crystals clearly shows a dominant excitation continuum, which exhibits a distinct temperature-dependent behavior from that of spin waves, and is rooted in strong quantum spin fluctuations. Further using the self-consistent-Gaussian-approximation method, we determine that the fourth- and fifth-nearest-neighbor exchange interactions are dominant. These two bonds together form a unique three-dimensional network of corner-sharing tetrahedra, which we name as a "hypertrillium" lattice. Our results provide direct evidence for the existence of QSL features in K{2}Ni_{2}(SO_{4})_{3} and highlight the potential for the hypertrillium lattice to host frustrated quantum magnetism.
连续自旋激发被广泛认为是量子磁体中新型自旋态的标志之一，比如量子自旋液体（QSLs）。在此，我们报告在K₂Ni₂(SO₄)₃中观察到了这类激发，它由两组相交的自旋为1（Ni²⁺）的三棱晶格组成。我们对单晶进行的非弹性中子散射测量清楚地显示出一个占主导的激发连续体，其表现出与自旋波截然不同的温度依赖行为，并且源于强烈的量子自旋涨落。进一步使用自洽高斯近似方法，我们确定第四和第五近邻交换相互作用占主导。这两个键共同形成了一个独特的由共角四面体组成的三维网络，我们将其命名为“超三棱”晶格。我们的结果为K₂Ni₂(SO₄)₃中存在QSL特征提供了直接证据，并突出了超三棱晶格承载受挫量子磁性的潜力。
