Chirality waves in two-dimensional magnets

Electron, as a particle with spin 1/2, moving though a magnetic material with non-coplanar magnetization pattern accumulates quantum mechanical (Berry) phase, characterized by the degree of non-coplanarity of the magnetic texture, or chirality. Until now metallic chiral magnets were thought to be quite rare and require either a fine tuning of the electron spectrum (nesting) or spin-orbit interactions. We show that two-dimensional magnets within a simple model of magnetism -- a Kondo lattice model -- favor a non-coplanar order (a distorted skyrmionic lattice) with unidirectional modulated chirality. Unlike recently observed chiral triangular skyrmion lattices supported by spin-orbit interaction and finite magnetic field (e.g. in MnSi), the chirality-wave order emerge at small-to-intermediate Kondo coupling strength in the absence of magnetic field or spin-orbit coupling