2024/09/27 by Nicolas M. Kawahala, Kawahala, Nicolas M., Daniel A. Matos +11 · 3 citations
Engineering · Physics and Astronomy · #Acoustic Wave Resonator Technologies #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Photonic Crystals and Applications #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.2409.18933
openalex publication_date 2024/09/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Naturally occurring van der Waals (vdW) materials are currently attracting significant interest due to their potential as low-cost sources of two-dimensional materials. Valuable information on vdW materials' interlayer interactions is present in their low-frequency rigid-layer phonon spectra, which are experimentally accessible by terahertz spectroscopy techniques. In this work, we have used polarization-sensitive terahertz time-domain spectroscopy to investigate a bulk sample of the naturally abundant, large bandgap vdW mineral clinochlore. We observed a strong and sharp anisotropic resonance in the complex refractive index spectrum near 1.13 THz, consistent with our density functional theory predictions for shear modes. Polarimetry analysis revealed that the shear phonon anisotropy reshapes the polarization state of transmitted THz waves, inducing Faraday rotation and ellipticity. Furthermore, we used Jones formalism to discuss clinochlore phononic symmetries and describe our observations in terms of its eigenstates of polarization. These results highlight the potential of exploring vdW minerals as central building blocks for vdW heterostructures with compelling technological applications.