Theoretical study on spin-1/2 antiferromagnetic kagome systems with a spin gap

从理论上研究了变形kagome体系Rb2Cu3SnF12和自旋球Mo72V30和W72V30，它们是顶点上有量子自旋的二十十二面体。对于Rb2Cu3SnF12，明确了高分辨率非弹性中子散射实验获得的低能谱中各分支的来源，并阐明了Dzyaloshinskii-Moriya相互作用的影响。对于Mo72V30，讨论了小的自旋间隙可以归因于具有D5h对称性的变形。对于W72V30，通过拉曼散射实验可以观测到自旋间隙内的低能单重态。

A deformed kagome system Rb2Cu3SnF12 and spin balls Mo72V30 and W72V30, which are icosidodecahedrons with quantum spins on their vertices, are studied theoretically. For Rb2Cu3SnF12, origin of each of branches in the low-energy spectrum obtained by high-resolution inelastic neutron scattering experiments is specified, and effects of Dzyaloshinskii-Moriya interactions are clarified. For Mo72V30, it is discussed that the small spin gap can be ascribed to the deformation with the D5h symmetry. For W72V30, it is possible to observe low-energy singlet states within the spin gap by Raman scattering experiments.