Work

Magnon valley Hall effect and tunable chiral edge transport in AB-stacked kagome lattices

Year: 2024

Type: article

Abstract: Our research investigates the magnon bands and their topological characteristics in a ferromagnetic pyrochlore lattice, with the Dzyaloshinskii–Moriya (DM) interaction playing a significant role. Given its kagome AB bilayer structure, the ferromagnetic exchange couplings, which may differ among the AB triangles, are further considered for their implications on the system’s magnetic properties. By employing the non-equilibrium Green’s function method, we explicitly demonstrate that the one-way chiral edge magnon transport is indeed regulated by the DM interaction direction (D→−D) and the exchange interaction of J1 and J2 (J1↔J2). Moreover, we demonstrate that the topological edge state predominantly resides along the edges and exhibits an oscillatory decay as it penetrates into the bulk in a non-equilibrium state. Although the chiral edge magnons and the corresponding energy current tend to travel along one edge from the hot region to the cold one, in the bulk, however, the energy current flows reversely from the cold to the hot region. The valley magnon Hall effects and chiral edge transport proposed here may be realized in the thin films of the insulating ferromagnet, such as Lu2V2O7. Thus, it will pave the way for a more extensive use of magnonics in future technologies.

Source: Journal of Applied Physics

DOI: 10.1063/5.0245162