Electron scattering from domain walls in ferromagnetic Luttinger liquids

We study the properties of interacting electrons in a one-dimensional conduction band coupled to bulk noncollinear ferromagnetic order. The specific form of noncollinearity we consider is that of an extended domain wall. The presence of ferromagnetic order breaks spin-charge separation and the domain wall introduces a spin-dependent scatterer active over the length of the wall lambda. Both forward and backward scattering off the domain wall can be relevant perturbations of the Luttinger liquid and we discuss the possible low-temperature phases. Our main finding is that backward scattering, while determining the ultimate low-temperature physics, only becomes important at temperatures T/J < exp(-lambda/lambda(+)), with J being the magnetic exchange and lambda(+) the backward scattering length scale. In physical realizations, lambda >> lambda(vertical bar) and the physics will be dominated by forward scattering, which can lead to a charge-conducting but spin-insulating phase. In a perturbative regime at higher temperatures we furthermore calculate the spin and charge densities around the domain wall and quantitatively discuss the interaction-induced changes.