3D Dirac Electrons and Large Thermoelectric Properties in CoGe

  • Naoya Kanazawa
Part of the Springer Theses book series (Springer Theses)


We have synthesized B20-type Co\(_{1-x}\)Fe\(_x\)Ge and Co\(_{1-y}\)Ni\(_y\)Ge by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. Non-doped CoGe shows a large figure of merit (\(ZT\approx 0.11\)) due to its low resistivity and large negative Seebeck coefficient (\(S=-82\,\mathrm {\mu V/K}\)) at 300 K. S shows a sign change with increasing Fe concentration, yielding its maximum value (\(S=28\,\mathrm {\mu V/K}\) at 300 K) at \(x=0.2\). The Boltzmann transport model can explain semi-quantitatively the experimental results, from which we conclude that the large positive or negative S originates from the asymmetric band structure composed of the Dirac cone and the flat band with sharp bends around the Fermi energy (\(E_F\)).


Thermoelectric Property Seebeck Coefficient Flat Band Dirac Cone Phonon Thermal Conductivity 
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  1. 1.
    G.D. Mahan, Solid State Phys. 51, 81 (1998)Google Scholar
  2. 2.
    Y. Nishino, S. Deguchi, U. Mizutani, Phys. Rev. B 74, 115115 (2006)ADSCrossRefGoogle Scholar
  3. 3.
    H.J. van Daal, P.B. van Aken, K.H.J. Buschow, Phys. Lett. A 49, 246 (1974)ADSCrossRefGoogle Scholar
  4. 4.
    R.J. Gambino, W.D. Grobman, A.M. Toxen, Appl. Phys. Lett. 22, 506 (1973)ADSCrossRefGoogle Scholar
  5. 5.
    I. Terasaki, Y. Sasago, K. Uchinokura, Phys. Rev. B 56, R12685 (1997)ADSCrossRefGoogle Scholar
  6. 6.
    N.W. Aschcroft, N.D. Mermin, Solid State Physics (Thomson Learning, London, 1976)Google Scholar
  7. 7.
    K. Kuroki, R. Arita, J. Phys. Soc. Jpn. 76, 083707 (2007)ADSCrossRefGoogle Scholar
  8. 8.
    G.Y. Guo, G.A. Botton, Y. Nishino, J. Phys. Condens. Matter 10, L119 (1998)ADSCrossRefGoogle Scholar
  9. 9.
    W. Koshibae, K. Tsutsui, S. Maekawa, Phys. Rev. B 62, 6869 (2000)ADSCrossRefGoogle Scholar
  10. 10.
    S. Asanabe, D. Shinoda, Y. Sasaki, Phys. Rev. 134, A774 (1964)ADSCrossRefGoogle Scholar
  11. 11.
    D.J. McNeill, R.M. Ware, Br. J. Appl. Phys. 15, 1517 (1964)ADSCrossRefGoogle Scholar
  12. 12.
    A. Sakai, F. Ishii, Y. Onose, Y. Tomioka, S. Yotsuhashi, H. Adachi, N. Nagaosa, Y. Tokura, J. Phys. Soc. Jpn. 76, 093601 (2007)ADSCrossRefGoogle Scholar
  13. 13.
    C.S. Lue, Y.K. Kuo, C.L. Huang, W.J. Lai, Phys. Rev. B 69, 125111 (2004)ADSCrossRefGoogle Scholar
  14. 14.
    C.C. Li, W.L. Ren, L.T. Zhang, K. Itoh, J.S. Wu, J. Appl. Phys. 98, 063706 (2005)ADSCrossRefGoogle Scholar
  15. 15.
    W.L. Ren, C.C. Li, L.T. Zhang, K. Ito, W.J. Lai, J. Alloys Compd. 392, 50 (2005)CrossRefGoogle Scholar
  16. 16.
    Y.K. Kuo, K.M. Sivakumar, S.J. Huang, C.S. Lue, J. Appl. Phys. 98, 123510 (2005)ADSCrossRefGoogle Scholar
  17. 17.
    E. Skoug, C. Zhou, Y. Pei, D.T. Morelli, Appl. Phys. Lett. 94, 022115 (2009)ADSCrossRefGoogle Scholar
  18. 18.
    F. Wald, S.J. Michalik, J. Less-Common Met. 24, 277 (1971)CrossRefGoogle Scholar
  19. 19.
    H. Takizawa, T. Sato, T. Endo, M. Shimada, J. Solid State Chem. 73, 40 (1988)ADSCrossRefGoogle Scholar
  20. 20.
    N. Kanazawa, Y. Onose, Y. Shiomi, S. Ishiwata, Y. Tokura, Appl. Phys. Lett. 100, 093902 (2012)ADSCrossRefGoogle Scholar
  21. 21.
    P. Blaha, K. Schwarz, G. Madsen, D. Kvasnicka, J. Luitz, An Augmented Plane Wave + Local Orbitals Program for Calculating Crystal Properties (Karlheinz Schwarz, Techn. Universität Wien, Austria, 2001)Google Scholar
  22. 22.
    J.P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996)ADSCrossRefGoogle Scholar
  23. 23.
    G.K.H. Madsen, D.J. Singh, Comput. Phys. Commun. 175, 67 (2006)ADSCrossRefMATHGoogle Scholar

Copyright information

© Springer Japan 2015

Authors and Affiliations

  1. 1.Department of Applied PhysicsThe University of TokyoTokyoJapan

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