Numerical Studies on Antiferromagnetic Skyrmions in Nanodisks by Means of A New Quantum Simulation Approach

Abstract: We employ a self-consistent simulation approach based on quantum physics here to study the magnetism of antiferromagnetic skyrmions formed on manolayer nanodisk planes. We find that if the disk is small and the Dzyaloshinsky-Moriya (DM) interaction is weak, a single magnetic vortex may be formed on the disk plane. In such a case, when uniaxial anisotropy normal to the disk plane is further considered, the magnetic configuration remains unchanged, but the magnetization is enhanced in that direction, and reduced in other two perpendicular orientations. Very similarly, a weak external magnetic field normal to the disk plane cannot obviously affect the spin structure of the nanodisk; however, when it is sufficiently strong, it can destroy the AFM skyrmion completely. On the other hand, by increasing DM interaction so that the disk diameter is a few times larger than the DM length, more self-organized magnetic domains, such as vortices and strips, will be formed in the disk plane. They evolve with decreasing temperature, however always symmetric about a geometric axis of the square unit cell. We further find that in this case introducing normal magnetic anisotropy gives rise to the re-construction of AFM single-vortex structure or skyrmion on the disk plane, which provides a way to create and/or stabilize such spin texture in experiment.