论文标题
旋转激发和旋转波隙中的铁磁weyl semimetal co $ _3 $ sn $ _2 $ s $ _2 $
Spin Excitations and Spin Wave Gap in the Ferromagnetic Weyl Semimetal Co$_3$Sn$_2$S$_2$
论文作者
论文摘要
我们报告了一项关于磁性Weyl半学Co $ _3 $ sn $ _2 $ s $ _2 $的全面中子散射研究，具有准二维结构。旋转波的平面内和平面外分散均以铁磁状态揭示，同样具有分散性但受阻的自旋兴奋持续到顺磁性状态。有效的交换相互作用已通过半古典的海森堡模型估计，以始终重现实验性$ T_C $和旋转刚度。但是，在$ t = 4 $ K处观察到的全旋距离= 2.3 $ MEV，比估计的磁各向异性能量大得多（$ \ sim0.6 $ MEV），而其温度依赖性表示来自Weyl fermions的显着贡献。这些结果表明，CO $ _3 $ sn $ _2 $ s $ _2 $是具有较大旋转刚度的三维相关系统，低能旋转动力学可能与拓扑电子状态相互作用。
We report a comprehensive neutron scattering study on the spin excitations in the magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$ with quasi-two-dimensional structure. Both in-plane and out-of-plane dispersions of the spin waves are revealed in the ferromagnetic state, similarly dispersive but damped spin excitations persist into the paramagnetic state. The effective exchange interactions have been estimated by a semi-classical Heisenberg model to consistently reproduce the experimental $T_C$ and spin stiffness. However, a full spin wave gap below $E_g=2.3$ meV is observed at $T=4$ K, much larger than the estimated magnetic anisotropy energy ($\sim0.6$ meV), while its temperature dependence indicates a significant contribution from the Weyl fermions. These results suggest that Co$_3$Sn$_2$S$_2$ is a three-dimensional correlated system with large spin stiffness, and the low-energy spin dynamics could interplay with the topological electron states.
