Propagation of THz magnons in a one-dimensional transition metal decorated holey graphyne strip with tunable bandgaps

Abstract

We report ab initio and model-Hamiltonian investigations of THz magnon propagation in a transition metal adatom decorated one-dimensional nanoscale strip derived from a holey graphyne (HGY) sheet. Using density functional theory (DFT) for the ab initio study of the system and then applying a tight binding model through Wannier functions, we obtain localized magnetic moments that can be studied using the Heisenberg spin model and linear spin wave theory. Our results show magnon propagation in the material with velocities reaching up to 5.5 km s⁻¹ along with bandgaps that can be tuned by up to 10% using an external magnetic field. These findings suggest that transition metal decorated one-dimensional HGY nanostrips act as atomically thin magnonic crystals with field tunable transmission bands, making them promising platforms for next-generation magnonic and wave-based computing devices operating in the terahertz range. Experimental realization through bottom–up synthesis, combined with spin wave spectroscopy or scattering measurements, could open new opportunities for exploring ultrafast spin dynamics in these materials.