Higher-order Topological Phases of Magnons in van der Waals Honeycomb Ferromagnets

Abstract

We theoretically propose a second-order topological magnon insulator by stacking the van der Waals honeycomb ferromagnets with antiferromagnetic interlayer coupling. The system exhibits Z${}_2$ topological phase, protected by pseudo-time-reversal symmetry (PTRS). An easy-plane anisotropy term breaks PTRS and destroys the topological phase. Nevertheless, it respects a magnetic two-fold rotational symmetry which protects a second-order topological phase with corner modes in bilayer and hinge modes along stacking direction. Moreover, an introduced staggered interlayer coupling establishes a Z${}_2$$\times$Z topology, giving rise to gapped topological surface modes carrying non-zero Chern numbers. Consequently, chiral hinge modes propagate along the horizontal hinges in a cuboid geometry and are robust against disorders. Our work bridges the higher-order topology and magnons in van der Waals platforms, and could be used for constructing topological magnonic devices.

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Cited by in corpus (9)

• Topological Phases in Magnonics
• Topological magnon gap engineering in van der Waals CrI${}_3$ ferromagnets
• Temperature-Induced Magnonic Chern Insulator in Collinear Antiferromagnets
• Anti-helical edge magnons in patterned antiferromagnetic thin film
• Intrinsic Spin Nernst Effect and Chiral Edge Modes in van der Waals Ferromagnetic Insulators: Dzyaloshinskii-Moriya vs. Kitaev Interactions
• Higher-order topology in twisted multilayer systems: a review
• Magnetic Moiré Systems: a review
• Finite-temperature topological magnons in honeycomb ferromagnets with sublattice asymmetries
• Engineering Two-Dimensional Hybrid-Order Topological Insulators via Trilayer Coupling