title: Highly dispersive scattering from defects in noncollinear magnets.
abstract: We demonstrate that pointlike defects in noncollinear magnets give rise to a highly dispersive structure in the magnon scattering, violating a standard paradigm of its momentum independence. For a single impurity spin coupled to a prototypical noncollinear antiferromagnet, we find that the resolvent is dominated by a distinct dispersive structure with its momentum dependence set by the magnon dispersion and shifted by the ordering vector. This feature is a consequence of umklapp scattering off the impurity-induced spin texture, which arises due to the noncollinear ground state of the host system. Detailed results for the staggered and uniform magnetization of this texture as well as the T matrix from numerical linear spin-wave theory are presented.
authors.affiliation: Institut für Theoretische Physik, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Brenig
authors.affiliation: Department of Physics, University of California, Irvine, California 92697, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Chernyshev