Hinge Magnons from Non-collinear Magnetic Order in Honeycomb Antiferromagnet

Abstract

We propose that non-collinear magnetic order in quantum magnets can harbor a novel higher-order topological magnon phase with non-Hermitian topology and hinge magnon modes. We consider a three-dimensional system of interacting local moments on stacked-layers of honeycomb lattice. It initially favors a collinear magnetic order along an in-plane direction, which turns into a non-collinear order upon applying an external magnetic field perpendicular to the easy axis. We exploit the non-Hermitian nature of the magnon Hamiltonian to show that this field-induced transition corresponds to the transformation from a topological magnon insulator to a higher-order topological magnon state with a one-dimensional hinge mode. As a concrete example, we discuss the recently-discovered monoclinic phase of the thin chromium trihalides, which we propose as the first promising material candidate of the higher-order topological magnon phase.

10 pages + 3 figures

References in corpus (4)

• Topological Origin of Non-Hermitian Skin Effects
• Topological Defects and Gapless Modes in Insulators and Superconductors
• Topological Transition in a Non-Hermitian Quantum Walk
• Topological magnon bands in a room temperature Kagome magnet

Cited by in corpus (7)

• Topological Phases in Magnonics
• Magnon corner states in twisted bilayer honeycomb magnets
• Higher-order Topological Phases of Magnons in van der Waals Honeycomb Ferromagnets
• Intrinsic topological magnons in arrays of magnetic dipoles
• Higher-order topology in twisted multilayer systems: a review
• Higher-order topology and corner triplon excitations in two-dimensional quantum spin-dimer models
• Topological edge states in dipolar zig-zag stripes