Pressure dependence of the single particle excitation in the charge-density-waveCeTe3system

We present data on the pressure dependence at 300 K of the optical reflectivity of ${\text{CeTe}}_3$, which undergoes a charge-density-wave (CDW) phase transition well above room temperature. The collected data cover an unprecedented broad spectral range from the infrared up to the ultraviolet, which allows a robust determination of the gap as well as of the fraction of the Fermi surface affected by the formation of the CDW condensate. Upon compressing the lattice there is a progressive closing of the gap, inducing a transfer of spectral weight from the gap feature into the Drude component. At frequencies above the CDW gap we also identify a power-law behavior, consistent with findings along the $R{\text{Te}}_3$ series (i.e., chemical pressure) and suggestive of a Tomonaga-Luttinger liquid scenario at high-energy scales. This set of data is placed in the context of our previous investigations of this class of materials and allows us to revisit important concepts for the physics of CDW state in layeredlike two-dimensional systems.