Magnetic materials with noncollinear spin structures and exotic topological textures have long been a focal point in condensed matter physics and spintronics. Curved magnetic materials are particularly intriguing because the direct coupling between geometric curvature and spin configurations can stabilize complex spin textures that are difficult to realize in planar systems. This unique geometric advantage offers an ideal platform for developing next-generation spintronic devices.
Recently, a collaborative research team published a study in Physical Review Letters. The team was led by Prof. ZHANG Jin from the National Center for Nanoscience and Technology, alongside Prof. SU Gang from the Institute of Theoretical Physics of the Chinese Academy of Sciences, and Prof. GU Bo from the University of Chinese Academy of Sciences. They successfully unveiled high-order vortex states and magnon orbital-angular-momentum hybridization in VSe2 single-walled nanotubes.
Through comprehensive density-functional theory and Landau-Lifshitz-Gilbert dynamical calculations, the researchers demonstrated that the magnetic ground states of VSe2 nanotubes are highly sensitive to their geometric diameters. The formation of these high-order vortex states arises from the intricate diameter-dependent competition between the nearest-neighbor ferromagnetic couplings and the longer-range antiferromagnetic couplings.
Furthermore, the team revealed a novel hybridization mechanism between magnon modes carrying different orbital angular momenta. They proved that, in the presence of magnetic anisotropy, these high-order vortex states enable a unique magnon-mode hybridization governed by specific orbital-angular-momentum selection rules.
Because magnetic vortex states with high orbital angular momentum can carry significantly richer information and exhibit remarkable robustness against external perturbations, they offer unprecedented advantages for information storage and processing. This study not only highlights the decisive role of geometry in reshaping microscopic magnetism but also opens up a new high-order regime for exploring topological spin textures in curved magnets.
Schematic illustration of high-order magnetic vortex states in magnetic nanotubes and the evolution of the magnetic ground state of VSe2 nanotubes with diameter (Image by LI Jiawen et al.)
Contact:
Prof. ZHANG Jin
National Center for Nanoscience and Technology
E-mail: jinzhang@nanoctr.cn
