Chirality Waves in Two-Dimensional Magnets
Magnetism is a cooperative phenomenon where spins of magnetic ions spontaneously orient relative to each other below a certain ordering temperature. In principle, arbitrarily complex magnetic orderings are possible; however, the magnetic states encountered in nature tend to be simple, the most common being ferromagnetism (one atom in magnetic unit cell, Fig. 1(a)] and antiferromagnetism (two distinct atoms in magnetic unit cell, Fig. 1(b)]. More complex orders, such as noncollinear spirals [Fig. 1(d)] and various noncoplanar orders [e.g., Fig. 1(e)] are less common, typically arising from the interplay of magnetic exchange interactions, spin-orbit (SO) coupling, frustrated lattice structure, and magnetic field.
How can I decide if magnetic calculation should be collinear or noncollinear?