SPICE Workshop on Chiral Phonons, July 29th - 31st 2025
Ji Eun Lee
Transverse optical phonons in PbTe are degenerate in the absence of a magnetic field. However, a recent study observed that the energies of left- and right-circularly polarized phonons split under an external magnetic field at low temperatures, exhibiting circular dichroism in the optical conductivity [1]. These observations suggest the existence of chiral phonons. To investigate these magneto-optical effects associated with chiral phonons, we performed terahertz transmission and Faraday rotation measurements on PbTe thin films under external magnetic fields using frequency-domain terahertz spectroscopy. Additionally, we employed a polarization converter and quarter-wave plate to probe differential optical responses to circularly polarized light and to confirm the presence of phonon chirality. Our study provides deeper insight into magnetization induced by chiral phonons.
Reference:
[1] A. Baydin et al., Phys. Rev. Lett. 128, 075901 (2022)