Theoretical Study of Magnon Spin Currents in Chromium Trihalide Hetero-bilayers: Implications for Magnonic and Spintronic Devices

The intriguing magnetic behavior of two-dimensional chromium trihalide materials holds great promises for spintronics and magnonics. Here, we study the stacking-dependent magnetism in (CrBr3/CrI3) hetero-bilayers by using first-principles calculations. We find that different stackings yield ferromagnetic ground states or favor an antiferromagnetic (AFM) interlayer coupling. Starting from ab initio results, we study the magnonic spectra and magnon spin textures in the hetero-bilayer. Based on our findings, we propose an experimental setup for the optical generation and electric detection of pure magnon spin currents in layered AFM (LAFM) (CrBr3/CrI3) hetero-bilayers. Furthermore, we propose a device to simultaneously realize magnon spin currents and topological domain walls in the hetero-bilayers. The advantages of (CrBr3/CrI3) hetero-bilayers over the (CrI3)2 homo-bilayers to realize magnon spin currents are highlighted. The interesting features of magnons in LAFM hetero-bilayers and their potential for spin-charge conversion could pave the way for their implementation in spin-based transistors and logic devices.