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arXiv · 2410.14797

Multimode vibrational coupling across the insulator-to-metal transition in 1T-TaS$_{2}$ in THz cavities

Giacomo Jarc·Shahla Yasmin Mathengattil·Angela Montanaro·Enrico Maria Rigoni·Simone Dal Zilio·Daniele Fausti
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Abstract

The use of optical cavities on resonance with material excitations allows controlling light-matter interaction in both the regimes of weak and strong coupling. We study here the multimode vibrational coupling of low energy phonons in the charge-density-wave material 1T-TaS$_{2}$ across its insulator-to-metal phase transition. For this purpose, we embed 1T-TaS$_{2}$ into THz Fabry-P\'erot cryogenic cavities tunable in frequency within the spectral range of the vibrational modes of the insulating phase and track the linear response of the coupled phonons across the insulator-to-metal transition. In the low temperature dielectric state, we reveal the signatures of a multimode vibrational strong collective coupling. The observed polariton modes inherit character from all the vibrational resonances as a consequence of the cavity-mediated hybridization. We reveal that the vibrational strong collective coupling is suppressed across the insulator-to-metal transition as a consequence of the phonon-screening induced by the free charges. Our findings emphasize how the response of cavity-coupled vibrations can be modified by the presence of free charges, uncovering a new direction toward the tuning of coherent light-matter interaction in cavity-confined correlated materials.

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Giacomo Jarc, Shahla Yasmin Mathengattil, Angela Montanaro, Enrico Maria Rigoni, Simone Dal Zilio, Daniele Fausti. 2024-10-18. Multimode vibrational coupling across the insulator-to-metal transition in 1T-TaS$_{2}$ in THz cavities. https://doi.org/10.1063/5.0231533

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