报告题目：Probing Spin Dynamics in Emergent Two-Dimensional van der Waals Magnets
报告人：李鹏教授 中国科学技术大学微电子学院
报告时间：4月7日（周五）10:00-12:00
报告地点：教2-314仙林校区
主办单位：350VIP浦京集团350VIP浦京集团
报告摘要：The discovery of 2D vdWs magnets has flourished a new endeavor of fundamental problems in magnetism, which can lead to applications in computing, storage, etc. We explore two emerging materials: Fe5GeTe2, a 2D vdWs room temperature magnet, and Cu(1,3-bdc), a quasi-2D topological magnon insulator with low Curie temperature. The static and dynamic magnetic properties were studied by vibrating sample magnetometry and broadband FMR spectroscopy at different temperatures. For both magnets, we have discovered that the Landé g-factor values deviate from g = 2, indicating contribution of orbital angular momentum to the magnetic moment. The FMR measurements reveal that Fe5GeTe2 has a damping constant comparable to Permalloy, and with reducing temperature, the linewidth broadens. The measurements also indicate that Fe5GeTe2 transitions from ferromagnetic to ferrimagnetic at lower temperatures. In Cu(1,3-bdc), the interplay of topology, spin excitations, and orbital magnetism presents a playground for exploring topological spintronics. While the differences of in-plane and out-of-plane Landé g-factor (Δg) and saturation magnetization (ΔMs) in Cu(1,3-bdc) are well correlated at low temperatures, they diverge at higher temperatures (T> 4 K). Our theoretical analyses show that topological orbital moment induced by thermally excited spin chirality results in the g-factor anisotropy at higher temperatures. Our work highlights the intriguing physics in the emergent vdW magnets and has proposed a new way to probe orbital moment in quantum magnets via g-factor analyses.
报告人简介：李鹏，中国科学技术大学微电子学院特任教授，博导。曾任美国斯坦福大学博士后研究员，奥本大学助理教授、博导。从事MRAM 及自旋电子器件领域的研究，与台积电、三星等公司开展了产业化合作研究并获多项专利。担任IEEE Transactions on Quantum Engineering 副主编，获2021 年度美国E. Powe Junior Faculty Enhancement Award。