Diameter-Controlled High-Order Vortex States and Magnon Hybridization in VSe_{2} Nanotubes

Curved magnets offer a rich phase diagram and hold great promise for next-generation spintronic technologies. This Letter establishes the paramount significance of high-order vortex states (e.g., 3φ with winding number n≥2) in VSe_{2} nanotubes, which uniquely enable magnonic functionalities fundamentally inaccessible to conventional magnetic systems, and additionally, the superposition of high-order vortex and helical states is identified. These states arise from diameter-dependent competition between the nearest-neighbor ferromagnetic (J_{1}) and longer-range antiferromagnetic (J_{2}/J_{3}) couplings, as jointly validated through density-functional theory calculations and Heisenberg modeling of phase diagrams. Based on the Landau-Lifshitz-Gilbert equation, we show that vortex states exhibit orbital angular momentum (OAM) hybridization governed by selection rules: magnetic anisotropy energy (MAE) and an external magnetic field couple the l mode to l±2(n1) and l±n, respectively. For the 3φ state, MAE couples the l=0 mode with l=±4, producing eight-petal magnon density patterns and providing a natural mechanism for generating high-OAM magnons. These findings establish a predictive theoretical framework for controlling high-order vortex states in curved magnets and highlight VSe_{2} nanotubes as a promising platform for exploring complex magnetism and for the development of future magnonic and spintronic devices.