Abstract
The peak figure of merit (ZT) of GeTe-based thermoelectric (TE) materials is typically attained in the high-temperature cubic phase, where the inevitable phase transition raises concerns over interfacial instability during operation. Therefore, developing high-performance rhombohedral GeTe below the phase transition temperature represents a more viable path toward practical applications. Herein, we propose a facile nanocomposite strategy to enhance the TE performance of rhombohedral GeTe by incorporating high-modulus TiB2 nanoparticles into Ge0.94Bi0.05Te matrix. We demonstrate that the nanoparticle-induced interfacial constraint effect contributes to increasing longitudinal elastic modulus and decreasing equivalent deformation potential, accounting for improved carrier mobility. Additionally, these TiB2 inclusions form heterogeneous interfaces that promote charge depletion and generate substantial thermal resistance, concurrently suppressing the heat transfer by carriers and phonons. Consequently, an extraordinary ZT of 2.66 at 613 K and a superior average ZT of 1.29 (300 ~ 613 K) are obtained in the rhombohedral GeTe-based composite. This work shows a paradigm for synergistically optimizing the electrical and thermal transports of emerging TE systems with nanoinclusions.
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Acknowledgments
This work was supported by the National Key R&D Program of China (2025YFF0524500 to Y.P.), National Natural Science Foundation of China (52502275 to J.C.Y.; 52401263 to Y.P.) and the Fundamental Research Funds for the Central University (2024CDJQYJCYJ-001 to J.C.Y.).
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J.-F.L. and X.Y.Z. contributed to the project supervision. Y.P. and J.C.Y. were responsible for the funding acquisition. J.C.Y. and Y.L.J. initiated the idea and drafted the manuscript. J.C.Y., X.D.L., and Y.L.J. designed the experiment and conducted principal investigations. C.C, J.-W.L., H.H.H., and L.S. helped to analyze the experimental data. T.X., B.-B.R., and G.Y.W. provided helpful discussions. B.L.M., Y.P., X.Y.Z., and J.-F.L. secured the experimental resources. All authors co-edited the manuscript.
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Yu, J., Liu, X., Jiang, Y. et al. Giant ZT enhancement in rhombohedral GeTe-based thermoelectric materials. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70793-6
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DOI: https://doi.org/10.1038/s41467-026-70793-6
