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Momentum-Resolved Direct Observation of Chiral Phonons in Elemental Tellurium
Qiyang Sun1, Songrui Hou2, Ayman H Said3
1Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee 37831, USA.
Physical Review Letters
|July 7, 2026
Summary
Researchers directly detected chiral acoustic phonons in elemental tellurium (Te). This discovery reveals circular atomic motion in acoustic modes, linking scattering intensity to phonon chirality.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Phononics
Background:
- Chiral phonons possess phonon angular momentum, but their behavior in acoustic branches is understudied.
- Understanding phonon chirality is crucial for exploring novel quantum phenomena and material properties.
Purpose of the Study:
- To directly detect and characterize chiral acoustic phonons in elemental tellurium (Te).
- To investigate the momentum-resolved behavior of phonon angular momentum in acoustic modes.
Main Methods:
- High-energy-resolution inelastic X-ray scattering (HXR-IXS) experiments.
- Atomistic modeling and simulations.
- Analysis of scattering intensity in nominally forbidden geometries.
Main Results:
- Direct detection of chiral acoustic phonons in elemental Te.
- Confirmation of circular atomic motion in longitudinal acoustic modes due to mixing with transverse modes.
- Established a link between unexpected scattering intensity and circular phonons.
Conclusions:
- Demonstrated the emergence of intrinsic phonon angular momentum in acoustic branches.
- Provided a framework for characterizing momentum-resolved phonon chirality.
- Opened new avenues for exploring chiral phenomena in condensed matter systems.
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