Giant Microwave Sensitivity of Magnetic Array by Long-Range Chiral Interaction Driven Skin Effect

TL;DR

This paper predicts a giant non-Hermitian skin effect in a magnetic nanowire array driven by long-range chiral interactions, enabling highly sensitive microwave detection through non-local spin-wave amplification.

Contribution

It demonstrates the suppression of interference in long-range chiral interactions to realize a non-Hermitian skin effect in magnetic systems, a novel approach for microwave sensing.

Findings

Weak microwave excitation at one edge causes large spin-wave response at the opposite edge.

Suppression of wave interference enhances non-Hermitian skin effect in magnetic arrays.

Potential for highly sensitive, non-reciprocal microwave detection.

Abstract

Non-Hermitian skin effect was observed in one-dimensional systems with short-range chiral interaction. Long-range chiral interaction mediated by traveling waves also favors the accumulation of energy, but has not yet showed non-Hermitian topology. Here we find that the strong interference brought by the wave propagation is detrimental for accumulation. By suppression of interference via the damping of traveling waves, we predict the non-Hermitian skin effect of magnetic excitation in a periodic array of magnetic nanowires that are coupled chirally via spin waves of thin magnetic films. The local excitation of a wire at one edge by weak microwaves of magnitude $\sim \mu{\rm T}$ leads to a considerable spin-wave amplitude at the other edge, i.e. a remarkable functionality useful for sensitive, non-local, and non-reciprocal detection of microwaves.