Magnon waveguide with nanoscale confinement constructed from topological magnon insulators

Abstract

Topological magnon insulators host spatially confined edge magnons brought about by the Dzyaloshinskii-Moriya interaction. Bringing two topological magnon insulators into contact results in topologically protected unidirectional interface magnons. These interface modes decay rapidly toward the bulk regions of the sample. As a result, heat and spin currents associated with these magnons are as well unidirectional and strongly confined to a few-nanometer-wide strip along the interface. On top of this, these interface currents follow any geometry owing to the topological nature of the magnons. In this theoretical study, we propose and analyze two recipes for composing magnon waveguides with nanoscale confinement, one from topologically different phases, another from identical phases. We further identify material classes to construct these magnon waveguides and propose an experiment to verify their topological nature.