Thermoelectric properties of composition-controlled Fe2TiSi-based full-Heusler thin films

Abstract

Abstract Fe2TiSi full-Heusler thin films were synthesized with a homogeneous single-phase structure and the composition was controlled in a wide range by deposition techniques. By detailed tuning of the film composition, the Seebeck coefficient reached −184 μV K−1, which is almost the maximum for the full-Heusler alloys, with a power factor of 3.9 mW K−2 m−1. The thermal conductivity was 3.5 W K−1 m−1 and first-principles calculations clarified that this small value may be due to alloy scatterings. Consequently, ZT reached 0.36 at room temperature without any heavy element doping, indicating that Fe2TiSi is one of the promising thermoelectric materials.