Fig. 3: Magnon gap in the dipolar honeycomb lattice.
From: Dipolar spin-waves and tunable band gap at the Dirac points in the 2D magnet ErBr3
a Simulation of the inelastic neutron cross-section S(κ, E) along the momentum transfer κ = (q, q, 0) for selected Ψ. Note the opening of a gap at κ = (2/3, 2/3, 0) between the acoustic and the lowest optical mode at the energy E ≈ 0.083 meV when the spin configuration given by angle Ψ is varied. The color bar represents the calculated intensity of the inelastic neutron cross-section. b Dependence of the magnon band gap as a function Ψ at κ = (2/3, 2/3, 0). c Calculation of the spin-wave dispersion close to the Dirac point for Ψ = −5.6 × 10−4 π, 0, and +5.6 × 10−4 π, respectively.
