Fig. 6: Schematic adjacency pattern for sub-matrix of the Hessian including HOI.
From: Impact of higher-order exchange on the lifetime of skyrmions and antiskyrmions
Schematic adjacency pattern for sub-matrix of the Hessian for four magnetic moments (mi, mj, mk, ml) in nearest neighbor distance of each other (see Fig. 1a). Each block ij corresponds to the 3 × 3 cartesian components of the second derivatives of the energy in Eq. (1) with respect to the magnetic moments. The block colors refer to the specific HOI term contributing (biquadratic (gray), 3-site (cyan) and 4-site (pink)) HOI.
