Inelastic Neutron Scattering for Direct Detection of Chiral Phonons

TL;DR

This paper introduces inelastic neutron scattering as a direct method to detect and analyze chiral phonons, enabling clear identification and exploration of their magnetic properties and dynamics in materials.

Contribution

It demonstrates INS as a versatile tool for direct detection of chiral phonons, distinguishing their modes, and accessing their magnetic moments, advancing phonon research.

Findings

INS can distinguish chiral from linear phonons.

Chiral phonon fingerprints are identified in tellurium.

INS reveals phonon magnetic moments and mode splitting in CeF3.

Abstract

Chiral phonons have attracted significant attention due to their potential applications in spintronics, superconductivity, and advanced materials, but their detection has predominantly relied on indirect photon-involved processes. Here, we propose inelastic neutron scattering (INS) as a direct and versatile approach for chiral phonon detection over a broad momentum-energy space. Leveraging INS sensitivity to phonon eigenmodes, we clearly distinguish linear, elliptical, and chiral phonons and determine phonon handedness through angle-resolved measurements. Using right-handed tellurium (Te) as a model system, we identify characteristic INS fingerprints that clearly separate chiral from linear phonons. Moreover, we show that INS can directly access phonon magnetic moments and the effective magnetic fields generated by chiral phonons, as evidenced by the pronounced mode splitting in CeF$_3$. Collectively, these results position INS as a powerful platform for comprehensive investigations of chiral-phonon dynamics and their associated quantum phenomena.