Abstract

AbstractMaterials with the TiNiSi structure have recently been highlighted as potential thermoelectric materials. Here we report the thermoelectric properties of TiNiX (X=Si and Ge). Both materials behave as defective metals or heavily doped degenerate semiconductors. Room temperature Seebeck coefficients are −45 μV K−1 (Si) and −20 μV K−1 (Ge) with electrical resistivities of 0.5–1 mΩ cm. The lattice thermal conductivities are 8 W m−1 K−1 (Si) and 6 W m−1 K−1 (Ge) at 360 K, which is promising in the absence of alloying. The calculated power factors and figures of merit remain small, with the largest S2/ρ=0.17 mW m−1 K−2 and peak zT=5×10−3 seen in TiNiSi near 300 K. Both compositions show Kondo behaviour at low‐temperatures, linked to the emergence of local moment magnetism, and have substantial magnetoresistance effects at 2 K. This work provides property characterisation for two members of this large class of intermetallic materials.

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