Electrical generation and tunable routing of domain wall spin waves in van der Waals antiferromagnets

Domain walls (DW) - topological defects separating oppositely oriented magnetic regions - are known to host confined spin wave modes [Phys. Rev. 124, 452 (1961)]. These modes are typically excited by power-hungry magnetic fields, which undermines the advantages of low-dissipation propagation and nanoscale confinement offered by spin waves in DWs. In this work, we show that layered van der Waals antiferromagnets with recently demonstrated voltage control of magnetic order [Nat. Nanotechnol. 13, 549 (2018)] provide an excellent platform to realize a voltage-based DW spin wave excitation scheme. The linear dispersion offered by these channels in the long-wavelength limit enables dispersionless transfer of spin information. Moreover, utilizing the interplay between charge and magnetization dynamics, we demonstrate that the group velocity of excited spin waves in the long-wavelength limit can be tuned via DC voltage. Our results provide a tunable, local, dispersionless, ultra-low dissipation means to excite and transport spin waves.