Terahertz Magnon Excitations and Switching in Non-Collinear Antiferromagnets

TL;DR

This paper demonstrates that non-collinear antiferromagnets can generate terahertz magnon excitations and be switched using spin currents, highlighting their potential for ultrafast memory and magnonic applications.

Contribution

It provides a numerical analysis of terahertz magnon excitations and switching mechanisms in non-collinear antiferromagnets, introducing a phase diagram for switching behavior.

Findings

Magnon frequency spectrum shows standing spin wave modes.

Switching phase diagram identifies conditions for ground state switching.

Magnets like Mn3Ge are promising for terahertz magnonics.

Abstract

We investigate how spatiotemporal spin polarized current can lead to terahertz frequency excitations in non-collinear antiferromagnets. By solving the Landau-Lifshitz-Gilbert equation numerically for non-collinear antiferromagnet, we show that the magnon frequency spectrum exhibits standing spin wave modes and depends on the thickness of Mn$_3$Ge in heterostructure Fe|Au|Mn$_3$Ge. Also, we analyze the switching process of ground state as a function of a spin current. We show a switching phase diagram, which contains switching and non-switching regions. Our work suggests non-collinear antiferromagnets as an efficient platform for terahertz magnonics and ultrafast memory devices.