Spin-wave scattering by an extended anisotropic and antisymmetric ladder defect

We investigate the scattering of spin waves in a two-dimensional square Heisenberg lattice containing an extended ladder-type bond defect. Within a semiclassical large- S approach, we derive analytical expressions for the magnon transmission coefficient and identify the conditions for perfect (resonant) transmission across the defect. We show that the presence of an antisymmetric Dzyaloshinskii–Moriya interaction induces chiral phase shifts that lead to momentum-dependent transparency windows and strong nonreciprocal (diode-like) magnon transport in the ferromagnetic regime. The positions and widths of the resonant channels can be tuned by the defect coupling, exchange anisotropy, and the strength of the Dzyaloshinskii–Moriya interaction. In contrast, antiferromagnetic magnons exhibit a qualitatively different scattering behavior, characterized by mode-selective resonances and fragmented rectification patterns that require finer parameter tuning. These findings demonstrate that ladder-type defects provide a simple and versatile platform for controlling magnon transport in two-dimensional magnetic systems. • We investigate spin-wave scattering in square lattices containing an extended ladder-type bond defect line. • The transmission of ferro and antiferromagnetic magnons is modified by combining anisotropic and antisymmetric interactions along the defect ladder. • Ferromagnetic magnon transport is transparent and strongly non-reciprocal under specific incidence conditions. • Antiferromagnetic magnon transport exhibits qualitatively different scattering behavior, showing selective resonances and a fragmented rectification pattern. • Our results highlight the extended ladder-type defect line as a flexible platform for engineering resonant and momentum-selective magnon transport.