Cui Qirui, Ge Yuqing, Bai Xiaocheng, Sassa Yasmine, Delin Anna
Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, SE-10691 Stockholm, Sweden.
Swedish e-Science Research Center, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
iScience. 2025 Aug 5;28(9):113291. doi: 10.1016/j.isci.2025.113291. eCollection 2025 Sep 19.
The ability to efficiently control topological magnetism is crucial for advancing technological applications and deepening our understanding of magnetic systems. Although emerging van der Waals (vdW) multiferroics present a promising frontier for energy-efficient spin manipulation, the control of topological magnetism remains challenging due to its scarcity in multiferroics. Here, we demonstrate that highly tunable merons and antimerons emerge in monolayer multiferroic (CCPS). The antiferroelectric-to-ferroelectric (AFE-FE) transition enhances exchange couplings, notably reducing meron density and increasing meron size during cooling. Merons exhibit unique dynamics, characterized by nontrivial attraction and annihilation processes, which generates distinct long-lived spin waves and reduces meron number difference between AFE and FE phases until they vanish. Importantly, ultrafast laser pulses can induce ferroelectricity-tunable merons from a uniform in-plane magnetization, re-leading to a large difference in meron density between the AFE and FE phases. These findings enhance our understanding of topological magnetism and open up exciting avenues for controlling the properties and dynamics of topological states through electrical and optical methods.
有效控制拓扑磁性的能力对于推动技术应用和深化我们对磁系统的理解至关重要。尽管新兴的范德华（vdW）多铁性材料为节能自旋操控提供了一个有前景的前沿领域，但由于其在多铁性材料中的稀缺性，拓扑磁性的控制仍然具有挑战性。在这里，我们证明了高度可调谐的磁子和反磁子出现在单层多铁性材料（CCPS）中。反铁电到铁电（AFE-FE）转变增强了交换耦合，在冷却过程中显著降低了磁子密度并增加了磁子尺寸。磁子表现出独特的动力学，其特征是非平凡的吸引和湮灭过程，这会产生独特的长寿命自旋波，并减小AFE和FE相之间的磁子数差异，直到它们消失。重要的是，超快激光脉冲可以从均匀的面内磁化诱导出铁电可调谐磁子，再次导致AFE和FE相之间磁子密度的巨大差异。这些发现增强了我们对拓扑磁性的理解，并开辟了通过电学和光学方法控制拓扑态性质和动力学的令人兴奋的途径。
