Orbital-selective band engineering realizes high zT in p-type Ru<sub>2</sub>Ti<sub>1-x</sub>Hf<sub>x</sub>Si full-Heusler thermoelectrics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41803083.
- Also identified by DOI 10.1038/s41467-026-69799-x and PMC identifier 13022361.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Heusler compounds have emerged as important thermoelectric materials due to their combination of promising electronic transport properties, mechanical robustness and chemical stability - key aspects for practical device integration. While a wide range of XYZ-type half-Heusler compounds have been studied for high-temperature applications, X<sub>2</sub>YZ-type full-Heuslers, often characterized by narrower band gaps, may offer potential advantages at different temperature regimes but remain less explored. In this work, the discovery of p-type Ru<sub>2</sub>Ti<sub>1-x</sub>Hf<sub>x</sub>Si full-Heusler thermoelectrics, exhibiting a high figure of merit zT = 0.7 over a broad range of temperatures 700-1000 K, is reported. These results not only represent the largest values known to date among full-Heusler materials but confirm earlier theoretical predictions that p-type Ru<sub>2</sub>TiSi systems would be superior to their n-type counterparts. Moreover, using a two-band model, electronic structure changes induced by the Hf substitution at the Ti site are unveiled and strategies to further improve zT up to zT > 1 are outlined. These findings highlight the untapped potential of new semiconducting full-Heusler phases and the crucial need for continued exploration of this rich materials class for thermoelectric applications.