Anisotropic manipulation of terahertz spin-waves by spin-orbit torque in a canted antiferromagnet

TL;DR

This paper demonstrates how electrical currents can control and manipulate terahertz-range spin waves in antiferromagnetic materials, paving the way for tunable terahertz sources for advanced communication technologies.

Contribution

It introduces a theoretical and numerical framework for anisotropic control of spin waves in AFMs using spin-orbit torque in heterostructures, highlighting new tunability mechanisms.

Findings

Spin wave spectra bifurcate into high- and low-frequency bands.

Electrical control enables anisotropic manipulation of spin-wave modes.

Potential for electrically tunable terahertz wave sources.

Abstract

We theoretically and numerically elucidate the electrical control over spin waves in antiferromagnetic materials (AFM) with biaxial anisotropies and Dzyaloshinskii-Moriya interactions. The spin wave dispersion in an AFM manifests as a bifurcated spectrum with distinct high-frequency and low-frequency bands. Utilizing a heterostructure comprised of platinum and the AFM, we demonstrate anisotropic control of spin-wave bands via spin currents with three-dimensional spin polarizations, encompassing both resonant and propagating wave modes. Moreover, leveraging the confined geometry, we explore the possibility of controlling spin waves within a spectral domain ranging from tens of gigahertz to sub-terahertz frequencies. The implications of our findings suggest the potential for developing a terahertz wave source with electrical tunability, thereby facilitating its incorporation into ultrafast, broadband, and wireless communication technologies.