Multipolar order in antiferromagnetic domain walls: application to MnPS₃ moiré superlattices

We study multipolar order in domain walls in easy-plane antiferromagnets in various geometries. We show that while the dipolar order vanishes for simple geometries, it stays finite for angled domain walls. Among the multipoles that we consider, we find that the octupolar order is largest regardless of the geometry of the domain wall. Next we perform atomistic simulations on twisted bilayer MnPS3 and show that the noncolinear order at small twist angles support both dipolar and octupolar order.