Multi-scale coherent magnons in magnetic moiré heterostructures

Summary: This proposal aims to characterize coherent magnon dynamics in magnetic moiré heterostructures. If successful, our study will establish a foundation for tuning magnon dissipation, propagation, and coupling to other excitations, advancing their potential for quantum information storage and transfer.

The characteristic timescale of the magnon oscillation is expected to span from picosecond to microsecond, reflecting the separation of length scales between atomic (∼ 1 nm) and moiré (∼ 10 nm), and hence the separation of the corresponding energy scales. Coherent magnon propagation is anticipated to occur over even larger length scales, ranging from a few to tens of micrometers. Characterizing these dynamics is essential for leveraging magnons as information carriers in magnetic heterostructures. To investigate these multi-scale spin excitations, we will employ a combined theoretical and experimental approach that spans a broad range of frequencies, from GHz to THz. The starting 2D magnet of choice will be the family of zigzag antiferromagnets MPX₃ (where M = transition metal and X = Se or S). This choice is motivated by their high magnetic transition temperatures and 1 strong coupling to phonons (FePS₃, FePSe₃) or excitons (NiPS₃), both of which can play a crucial role in shaping magnon dynamics through tunable hybridization effects in heterostructure engineering.