FTIR Reflectivity spectra of Thermoelectric K2Sb8Se13 crystals

Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity spectra of K₂Sb₈Se₁₃ crystals are reported and analyzed for the first time. Optical investigations are conducted with or without polarization, in two directions, parallel and perpendicular to the needles. The observed distinct optical anisotropy investigated by means of polarization dependent reflectivity measurements is discussed with respect to the strong structural anisotropy