Letter | Published:

Thermopower enhancement by encapsulating cerium in clathrate cages

Nature Materials volume 12, pages 10961101 (2013) | Download Citation

This article has been updated

Abstract

The increasing worldwide energy consumption calls for the design of more efficient energy systems. Thermoelectrics could be used to convert waste heat back to useful electric energy if only more efficient materials were available. The ideal thermoelectric material combines high electrical conductivity and thermopower with low thermal conductivity. In this regard, the intermetallic type-I clathrates show promise with their exceedingly low lattice thermal conductivities1. Here we report the successful incorporation of cerium as a guest atom into the clathrate crystal structure. In many simpler intermetallic compounds, this rare earth element is known to lead, through the Kondo interaction, to strong correlation phenomena including the occurrence of giant thermopowers at low temperatures2. Indeed, we observe a 50% enhancement of the thermopower compared with a rare-earth-free reference material. Importantly, this enhancement occurs at high temperatures and we suggest that a rattling-enhanced Kondo interaction3 underlies this effect.

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Change history

  • 06 November 2013

    In the version of this Letter originally published online, in Fig. 1a caption, '2a (6c)' should have read '2a (6d)'. This error has now been corrected in all versions of the Letter.

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Acknowledgements

We acknowledge financial support from the Austrian Science Fund (projects P19458-N16, TRP 176-N22 and I623-N16) and the European Research Council (Advanced Grant QuantumPuzzle, no. 227378), and help from T. Pippinger and R. Miletich-Pawliczek (Vienna University) during single-crystal XRD measurements on La–BAS. TEM images were made by J. Bernardi and M. Stöger-Pollach at USTEM (Vienna University of Technology).

Author information

Affiliations

  1. Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria

    • A. Prokofiev
    • , A. Sidorenko
    • , M. Ikeda
    • , R. Svagera
    • , M. Waas
    • , H. Winkler
    •  & S. Paschen
  2. X-Ray Center, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria

    • K. Hradil
  3. Walther-Meißner-Institute for Low Temperature Research, Walther-Meißner-Straße 8, 85748 Garching, Germany

    • K. Neumaier

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Contributions

A.P. and S.P. designed the research. A.P. synthesized the material; A.S., M.I., R.S., M.W., H.W., K.N. and K.H. performed the measurements. A.P., A.S., H.W., K.H. and S.P. analysed the data. A.P., A.S. and S.P. prepared the manuscript.

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The authors declare no competing financial interests.

Corresponding authors

Correspondence to A. Prokofiev or S. Paschen.

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https://doi.org/10.1038/nmat3756

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