Enhancement of topological magnon-driven spin currents through local edge strain in CrI${}_3$ nanoribbons

This work describes topological magnon transport in zigzag CrI${}_3$ nanoribbons (ZNR) in presence of edge strain. Exchange coupling terms under strain are obtained from first-principles calculations, and the topological properties are introduced \emph{via} second-neighbor Dzyaloshinskii-Moriya interactions. The magnon Hamiltonian is calculated using linear spin-wave theory and the Holstein-Primakoff transformation. Then, we use non-equilibrium Green’s function method to calculate the spin-wave-generated currents in ribbons with different edge strain. Our calculations show the formation of strongly localized edge topological magnons within the gap for DMI values slightly higher than the ones reported experimentally and in the presence of a tensile edge strain of the order of 3%. The magnon-mediated topological spin transport calculations shows an increase of the spin current and characteristic decay length in tensile-strained CrI${}_3$ nanoribbons compared with unstrained ones. Our findings demonstrate that straintronics provides a powerful route to harness and control topological magnons in two-dimensional magnetic materials.