Remarkable properties of two-dimensional (2D) layer magnetic materials, which include spin filtering in magnetic tunnel junctions and the gate control of magnetic states, were demonstrated recently^{1,2,3,4,5,6,7,8,9,10,11,12}. Whereas these studies focused on static properties, dynamic magnetic properties, such as excitation and control of spin waves, remain elusive. Here we investigate spin-wave dynamics in antiferromagnetic CrI₃ bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique. Monolayer WSe₂ with a strong excitonic resonance was introduced on CrI₃ to enhance the optical excitation of spin waves. We identified subterahertz magnetic resonances under an in-plane magnetic field, from which the anisotropy and interlayer exchange fields were determined. We further showed tuning of the antiferromagnetic resonances by tens of gigahertz through electrostatic gating. Our results shed light on magnetic excitations and spin dynamics in 2D magnetic materials, and demonstrate their potential for applications in ultrafast data storage and processing.

最近在^{1,2,3,4,5,6,7,8,9，}二维（2D）层磁性材料的显着特性包括磁隧道结中的自旋滤波和磁态的栅极控制。^10,11,12。这些研究集中于静态特性，而动态磁特性（如自旋波的激发和控制）仍然难以捉摸。在这里，我们使用超快光泵浦/磁光Kerr探针技术研究反铁磁CrI ₃双层中的自旋波动力学。单层WSE ₂具有较强的激子的共振是显色指数推出₃增强自旋波的光激发。我们确定了平面内磁场下的太赫兹磁共振，从中可以确定各向异性和层间交换场。我们进一步展示了通过静电门控通过数十千兆赫兹对反铁磁共振产生的调谐。我们的结果揭示了2D磁性材料中的磁激发和自旋动力学，并证明了其在超快数据存储和处理中的应用潜力。