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arXiv · 2211.15748

Detection of phonon helicity in nonchiral crystals with Raman scattering

Selçuk Parlak·Sayandip Ghosh·Ion Garate
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Abstract

Recently, it has been predicted that the Berry curvature of electrons can produce an angular momentum for phonons. In systems with time-reversal symmetry, the direction of the phonon angular momentum is locked to the phonon wave vector. Accordingly, this phenomenon has received the name of ``phonon helicity". Here, we present a theory to unveil the signatures of such phonon helicity using Raman scattering. We show that the intensity of Raman scattering for circularly polarized light in BaMnSb$_2$ (a prototypical nonchiral Dirac insulator) changes under a reversal of the phonon wave vector, and that the phonon helicity can be inferred from that change. We compare our results to recent reports of Raman-based detection of phonon angular momentum in chiral crystals.

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Selçuk Parlak, Sayandip Ghosh, Ion Garate. 2022-11-28. Detection of phonon helicity in nonchiral crystals with Raman scattering. https://doi.org/10.1103/physrevb.107.104308

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