Valley-polarized domain wall magnons in 2D ferromagnetic bilayers

Area of Science:

• Condensed Matter Physics
• Spintronics
• Topological Materials

Background:

• Valleytronics utilizes electron valley degrees of freedom for novel functionalities.
• Topological valley-polarized electrons in bilayer graphene domain walls are key for valleytronics.
• Magnonic domain wall excitations in 2D ferromagnetic bilayers (FBL) are investigated.

Purpose of the Study:

• To explore the role of Dzyaloshinskii-Moriya interaction (DMI) and electrostatic doping (ED) on magnons in FBL domain walls.
• To investigate the potential for topological valley-polarized magnons in FBL.

Main Methods:

• Theoretical analysis of 1D magnons confined to layer stacking domain walls in FBL.
• Examination of the influence of DMI and ED on magnon properties.
• Investigation of DMI-free FBL systems.

Main Results:

• DMI and ED enrich FBL topology, but domain wall magnons lack a defined valley index.
• DMI-free FBL layer stacking domain walls act as 1D channels for ballistic transport.
• Topological valley-polarized magnons are identified in DMI-free FBL domain walls.

Conclusions:

• Layer stacking domain walls in DMI-free FBL support topological valley-polarized magnons.
• These findings offer a pathway towards magnon valleytronic devices using atomically thin topological magnetic materials.