  Interacting impurity spins adsorbed on surfaces have been suggested as basic
components for applications in quantum computation and spintronics. Such spins
usually prefer a parallel or antiparallel configuration, but weakly
non-collinear alignments are possible due to the Dzyaloshinskii-Moriya
interaction (DMI) that arises in the presence of relativistic spin-orbit
coupling. Here, we show that an effective DMI can emerge purely from
superconducting correlations without any spin-orbit interaction. We give an
analytical proof and provide a numerical study which shows that DMI arises in
mixed-parity superconductors solely from the superconducting pairing. These
results enable a way to engineer spin textures using the superconducting phase
transition.
