Figure 6: Numerically calculated SW dispersion relations.

(a) Calculated SW dispersion relations for different IDM energy densities. The green box indicates that SW wavevector range of our BLS experiment. (b) The IDM energy density from the SW dispersion relations as a function of tFM−1. Inset: calculated SW dispersion relations for various tFM−1 from 2 ML to 20 ML when δ0 (SD/Jexa) is 0.1. The vertical line indicate the kx=0. The SW frequencies at kx=0 increase with increasing tFM.