Abstract Scope |
Half-Heusler phases possess compositional flexibility for designing good thermoelectric (TE) properties. We show that traditional alloying guided by bandstructure calculations can lead to exceptionally high ZT. We first presented the well-studied p-type Hf0.3Zr0.7CoSn0.3Sb0.7 alloys, previously reported to have ZT near 0.8, resonantly doped with <1 at.% metallic Al, which can achieve a remarkable ZT~1.5 near 1000 K [1]. The results are discussed in terms of a local anomaly in the density-of-states near the Fermi energy and unexpected grain structure refinement. The effective mass is enhanced from ~ 7 to 10me. Preliminary study of n-type HH compositions has yielded even higher ZT above 2 [2]. The state-of-the-art ZT values obtained through a conventional and non-complex approach should reinvigorate the exploration of high thermoelectric performance in ordinary alloy systems.
1. A. Benton, S. Akhanda, J. Qi, M. Zebarjadi, D. Singh, J. Poon, Mater. Today Phys. 28, 100900 (2022).
2. In preparation. |