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Description:

Decoupling charge and heat transport is essential for optimizing thermoelectric materials. Strategies to inhibit lattice-driven heat transport, however, also compromise carrier mobility, limiting the performance of most thermoelectrics, including Fe2VAl Heusler compounds. Here, we demonstrate an innovative approach, which bypasses this tradeoff: via liquid-phase sintering, we incorporate the archetypal topological insulator Bi1 – xSbx between Fe2V0.95Ta0.1Al0.95 grains. Structural investigations alongside extensive thermoelectric and magneto-transport measurements reveal distinct modifications in the microstructure, a reduced lattice thermal conductivity and a simultaneously enhanced carrier mobility arising from topologically protected charge
transport along the grain boundaries. This yields a huge performance boost, resulting in one of the highest figure of merits among both half- and full-Heusler compounds, z ≈ 1.6 × 10−3 K−1 (zT ≈ 0.5) at 295 K. Our findings highlight the potential of topological-insulating secondary phases to decouple charge and heat transport and call for more advanced theoretical studies of multiphase composites.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: thermoelectric

Date published: 2025-03-26

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Communications (ISSN: 20411723) vol. 16 issue. 1 2976

Funding:

• MEXT | Japan Science and Technology Agency JPMJMI19A1
• Lions Clubs International Foundation
• Lions Club Wien St. Stephan
• Deutsche Forschungsgemeinschaft 520487260

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1038/s41467-025-57250-6

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Updated at: 2025-11-10 16:30:43 +0900

Published on MDR: 2025-11-10 16:25:02 +0900