Fig. 4: Berry phase and Berry curvature in the dipolar honeycomb lattice.
From: Dipolar spin-waves and tunable band gap at the Dirac points in the 2D magnet ErBr3
a The Berry phase associated with the Dirac cone (Ψ = 0°) is either +π (represented in yellow) or –π (blue). The Berry curvature Ω(k) in ErBr3 calculated for the acoustic magnon branch: b Ψ = −5°, c Ψ = 5°, Ψ = 30° and Ψ = 55°. Ψ is the angle representing the spin configuration. The Brillouin zone boundary is outlined with dashed lines. The color bar shows the magnitude of the Berry curvature.
