Cavity-mediated thermal control of metal-to-insulator transition in 1T-TaS2

Placing quantum materials into optical cavities can provide a unique platform to control
quantum cooperative properties of matter, in the regimes of both weak and strong light-matter coupling. Here we show the first experimental evidence of the reversible touchless control of a metal-to-insulator phase transition in the charge density wave material 1T-TaS2 embedded in a tunable THz optical cavity. The switch between conductive and insulating behavior, which is obtained by mechanically tuning the distance between the cavity mirrors and their alignment, is related to a significant renormalization of the sample temperature. This suggests a Purcell-like scenario in which the spectral profile of the cavity modifies the energy exchange between the material and the external electromagnetic field. Our findings uncover a new path to control the thermodynamics and macroscopic transport properties of quantum materials by engineering their electromagnetic environment.