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TRR 360 Seminar:

Cavity electrodynamics of correlated materials in Fabry-Pèrot optical resonators

Giacomo Jarc

February 11 @ 16:00 17:00

Cavity electrodynamics of correlated materials in Fabry-Pèrot optical resonators

Dr. Giacomo Jarc

Friedrich-Alexander-Universität, Erlangen-Nürnberg

 

The possibility of engineering collective properties of bulk materials through cavity electrodynamics has been so far mostly explored in theoretical works and theory-based experimental proposals [1]. Only recently, the development of new experimental platforms [2, 3] has started to unlock the full potential of cavity-control of solid-state quantum materials and shed light on new pathways for light-matter coupling in a cavity-confined environment.

In this seminar, I will discuss our recent study on the cavity-mediated thermal control of the metal-to-insulator transition in the charge-density-wave (CDW) material 1T-TaS2 [4], which show the possibility of reversible cavity-manipulation of a phase transition in a correlated material. We embed 1T-TaS2 into cryogenic tunable terahertz cavities [3] and show that a switch between conductive and insulating behaviours, triggered by a large change in the sample temperature, is obtained by mechanically tuning the distance between the cavity mirrors and their alignment. The large thermal modification observed is indicative of a Purcell-like scenario in which the spectral profile of the cavity modifies the energy exchange between the material and the external electromagnetic field [5].

When the cavity is tuned resonantly to the multiple IR-active vibrations of the CDW dielectric phase of 1T-TaS2, we reveal the THz signatures of a multimode vibro-polariton mixing, originating from the collective strong coupling of the CDW vibrations with the cavity field [6]. The estimated components of the polaritonic wave-functions show that the observed multimode polaritons have character from all the vibrational resonances as a consequence of the cavity-mediated hybridization. The Rabi splittings between the hybridized phonons are suppressed across the insulator-to-metal transition as a consequence of the screening of the free charges. Intriguingly, we reveal that in proximity of the phase transition, the phonon dissipations trigger the onset of a weak vibrational coupling regime in the cavity-confined material.

When instead the cavity frequency is tuned within the spectral range of the continuum Drude excitation of 1T-TaS2, we reveal that the quality factor of the cavity, which quantifies the dissipative response of the coupled system, is sensitive to the material phase. We measure indeed the lifetime of the cavity photons to decrease passing from the insulating to the metallic state. This evidence points to a scenario in which the free charges responsible for the Drude excitation can effectively couple to the cavity field and subsequently modulate the light-matter coupling within the Fabry-Pèrot resonator.

Our findings show how cavity electrodynamics can play a role in the intricate equilibrium physics of complex materials, possibly providing a new tool to control and engineer their cooperative properties.

 

[1] F. Schlawin, D. M. Kennes, and M. A. Sentef., “Cavity quantum materials”, Applied Physics Reviews 9, 011312 (2022).

[2] G. Jarc, S. Y. Mathengattil, F. Giusti, M. Barnaba, A. Singh, A. Montanaro, F. Glerean, E. M. Rigoni, S. Dal Zilio, S. Winnerl, and D. Fausti, “Tunable cryogenic terahertz cavity for strong light-matter coupling in complex materials”, Rev. Sci. Instrum. 93, 033102 (2022).

[3] F. Appugliese, J. Enkner, G. Parravicini-Bagliani, M. Beck, C. Reichl, W. Wegscheider, G. Scalari, C. Ciuti, and J. Faist, “Breakdown of topological protection by cavity vacuum fields in the integer quantum Hall effect”, Science 375, 6584, 1030-1034 (2022).

[4] G. Jarc, S. Y. Mathengattil, A. Montanaro, F. Giusti, E. M. Rigoni, R. Sergo, F. Fassioli, S. Winnerl, S. Dal Zilio, D. Mihailovic, P. Prelovsek, M. Eckstein, and D. Fausti, “Cavity-mediated thermal control of metal-to-insulator transition in 1T-TaS2”, Nature 622, 487-492 (2023).

[5] F. Fassioli, J. Faist, M. Eckstein, and D. Fausti, “Controlling radiative heat through cavity electrodynamics”, arXiv:2403.00851v1 [physics.optics] (2024).

[6] G. Jarc, A. Montanaro, S. Y. Mathengattil, E. M. Rigoni, S. Dal Zilio, and D. Fausti, “Multimode vibrational coupling across the insulator-to-metal transition in 1T-TaS2 in THz cavities”, J. Chem. Phys. 161, 154711 (2024).

Venue

University of Augsburg

Room 288 (S) + Zoom

Details

Date:
February 11
Time:
16:00 – 17:00
Event Category:

Organizer

Joachim Deisenhofer