Pressure dependence of the optical properties of the charge-density-wave compound LaTe2

We report the pressure dependence of the optical response of LaTe2, which is deep in the charge-density-wave (CDW) ground state even at 300 K. The reflectivity spectrum is collected in the midinfrared spectral range at room temperature and at pressures between 0 and 7 GPa. We extract the energy scale due to the single-particle excitation across the CDW gap and the Drude weight. We establish that the gap decreases upon compressing the lattice while the Drude weight increases. This signals a reduction in the quality of nesting upon applying pressure, therefore inducing a lesser impact of the CDW condensate on the electronic properties of LaTe2. The consequent suppression of the CDW gap leads to a release of additional charge carriers, manifested by the shift of weight from the gap feature into the metallic component of the optical response. On the contrary, the power-law behavior, seen in the optical conductivity at energies above the gap excitation and indicating a weakly interacting limit within the Tomonaga-Luttinger liquid scenario, seems to be only moderately dependent on pressure.