Thermoelectric properties and Kondo transition in the pseudo-gap metals TiNiSi and TiNiGe
Abstract
Materials 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.
Citation
Downie , R A , Kennedy , B , Biswas , R , Smith , R & Bos , J-W G 2023 , ' Thermoelectric properties and Kondo transition in the pseudo-gap metals TiNiSi and TiNiGe ' , Zeitschrift für Anorganische und Allgemeine Chemie , vol. 649 , no. 14 , e202300055 . https://doi.org/10.1002/zaac.202300055
Publication
Zeitschrift für Anorganische und Allgemeine Chemie
Status
Peer reviewed
ISSN
0044-2313Type
Journal article
Description
Funding: Engineering and Physical Sciences Research Council EP/J000884/1, EP/W037300/1 (RAD, BFK).Collections
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