Topological Magnon Hall Effect — Kagome Lattice

On a kagome lattice ferromagnet with Dzyaloshinskii-Moriya interaction, magnon bands acquire Berry curvature and a non-zero Chern number, giving rise to a thermal Hall effect analogous to the quantum Hall effect for electrons. The colored band structure shows topologically non-trivial gaps.

DM Interaction
Chern #1:+1
Chern #2:0
Chern #3:-1
Legend
Band 1 (Chern +1)
Band 2 (flat-like)
Band 3 (Chern -1)
Berry curvature peaks
at band touchings
Kagome: 3 sites/cell
→ 3 magnon bands
Hover lattice to see
local spin excitations