Magnetic topological quasiparticles in 2D van der Waals magnets engineered by layer stacking

Skyrmions, antiskyrmions, and bimerons are swirling magnetic textures with nontrivial topologies in magnetic materials. Unlike the widely investigated skyrmions, antiskyrmions and bimerons are rarely found due to the requirement of the anisotropic Dzyaloshinskii-Moriya interaction (DMI). Here we propose to exploit the recently demonstrated van der Waals (vdW) assembly of two-dimensional (2D) materials that are non-polar in the bulk form to break inversion symmetry and create conditions for the emergence of anisotropic DMI in 2D magnets.¹ We demonstrate, based on symmetry analyses and first-principles calculations, that this strategy is a promising platform to realize antiskyrmions and bimerons. The polar layer stacking of two centrosymmetric magnetic monolayers, such as CrI₃, can efficiently lower the symmetry, resulting in anisotropic DMI that supports antiskyrmions or bimerons depending on the magnetic anisotropy of the 2D magnet. The DMI is reversible by switching the ferroelectric polarization inherited from the polar layer stacking, offering the ability to control antiskyrmions or bimerons by an electric field. Moreover, we find that the magnetic anisotropy of CrI₃ can be efficiently changed by Mn doping, creating a possibility to control the size of antiskyrmions and bimerons. Our work opens a new direction to generate and control magnetic quasiparticles other than skyrmions.