Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

• 作者: Chang Liu JianLei Shen JiaCheng Gao ChangJiang Yi Di Liu Tao Xie Lin Yang Sergey Danilkin GuoChu Deng WenHong Wang ShiLiang Li YouGuo Shi HongMing Weng EnKe Liu HuiQian Luo
• 来源期刊: 中国科学：物理学 力学 天文学（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: Editor's Focus
• 页码范围: 1-9
• 页数: 9页
• 语种: 英文

摘要

We report a comprehensive neutron scattering study on the spin excitations in the magnetic Weyl semimetal Co3Sn2S2 with a quasi-two-dimensional structure.Both in-plane and out-of-plane dispersions of the spin waves were revealed in the ferromagnetic state.Similarly,dispersive but damped spin excitations were found in the paramagnetic state.The effective exchange interac-tions were estimated using a semi-classical Heisenberg model to consistently reproduce the experimental Tc and spin stiffness.However,a full spin wave gap below Eg = 2.3 meV was observed at T = 4 K.This value was considerably larger than the estimated magnetic anisotropy energy(～0.6 meV),and its temperature dependence indicated a significant contribution from the Weyl fermions.These results suggest that Co3Sn2S2 is a three-dimensional correlated system with a large spin stiffness,and the low-energy spin dynamics can interplay with the topological electron states.