Enhancing Thermoelectric Properties through Control of Nickel Interstitials and Phase Separation in Heusler/Half-Heusler TiNiSn Composites.

Thermoelectric devices, which allow direct conversion of heat into electrical energy, require materials with improved figures of merit ( z T ) in order to ensure widespread adoption. Several techniques have been proposed to increase the z T of known thermoelectric materials through the reduction of thermal conductivity, including heavy atom substitution, grain size reduction and inclusion of a semicoherent second phase. The goal in these approaches is to reduce thermal conductivity through phonon scattering without modifying the electronic properties.

Thermoelectric performance and the role of anti-site disorder in the 24-electron Heusler TiFeSn.

Heusler compounds XY Z with 24 valence electrons per formula unit are potential thermoelectric materials, given their thermal and chemical stability and their relatively earth-abundant constituent elements. We present results on the 24-electron compound TiFeSn here. First principles calculations on this compound suggest semiconducting behavior.