Magnon band topology in spin-orbital coupled magnets: classification and application to $\alpha$-RuCl${}_3$

Abstract

In spite of flourishing studies on the topology of spin waves, a generic framework to classify and compute magnon band topology in non-collinear magnets is still missing. In this work we provide such a theory framework, by mapping an arbitrary linear spin wave into a local free-fermion Hamiltonian with exactly the same spectrum, symmetry implementation and band topology, which allows for a full classification and calculation on any topological properties of magnon bands. We apply this fermionization approach to honeycomb Kitaev magnet $\alpha$-RuCl${}_3$, and show the existence of topologically protected magnon band crossings, and field-induced magnon Chern bands under small magnetic fields.

6+10 pages, 4 figures, 2 tables, references updated

Cited by in corpus (7)

• Topological Correspondence between Hermitian and Non-Hermitian Systems: Anomalous Dynamics
• Non-Hermiticity and topological invariants of magnon Bogoliubov-de Gennes systems
• Rotation-symmetry-enforced coupling of spin and angular momentum for p-orbital bosons
• A simple approach to characterizing band topology in bosonic pairing Hamiltonians
• Squeezing-induced Topological Gap Opening on Bosonic Bogoliubov Excitations
• Symmetry-protected topological magnons in three dimensional Kitaev materials
• Entanglement-enabled symmetry-breaking orders