Thermoelectric properties of lanthanum sulfide

Abstract

The Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall effect have been studied in γ-phase La3−xS4 (LaSy) in the composition range 0.04≤x≤0.3 (1.35≤y≤1.48) in order to ascertain its suitability for high-temperature (300 to 1400 K) thermoelectric energy conversion. In this temperature and composition range the material behaves as an extrinsic semiconductor whose degenerate carrier concentration is controlled by the stoichiometric ratio of La to S. A maximum figure-of-merit (Z) of ∼5×10−4 K−1 at a composition x=0.3, y=1.48 (LaS1.48) was obtained.