High-pressure infrared spectroscopy on quasi-one-dimensional metals

The polarization-dependent mid-infrared optical responses of the two quasi-one-dimensional metals β-Na0.33V2O5 and LaTiO3.41 were studied at room temperature as a function of pressure. An observed increase of the low-frequency reflectivity perpendicular to the conducting chains suggests the onset of a pressure-induced dimensional crossover. The pressure dependences of the pronounced mid-infrared band observed for both compounds along the conducting axis are discussed in terms of polaronic excitations.