Figure 2

Overview of the NEB method. A summary of the Nudged Elastic Band method in a system parametrised by two variables. The surface height indicates the energy plotted for all points in this two-dimensional phase space. A set of specific magnetic configuration is shown through spheres, each being one image of the method. For a particular image Y _i of the initial energy band, we show the effective (total) force G, the gradient component perpendicular to the band ∇ _μ E|_⊥ (μ = μ _s s as the magnetic moment, see Methods for details), the tangent to the band t and the spring force F. The height of the surface E _i  = E(Y _i ) shows the energy of image i. At the extrema of the band, the magnetic configurations are fixed and localised at energy minima.