Band-filling dependence of thermoelectric properties in B20-type CoGe

N. Kanazawa; Y. Onose; Y. Shiomi; S. Ishiwata; Y. Tokura

doi:10.1063/1.3691260

Band-filling dependence of thermoelectric properties in B20-type CoGe

N. Kanazawa, Y. Onose, Y. Shiomi, S. Ishiwata, Y. Tokura

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12 Citations (Scopus)

Abstract

We have synthesized B20-type Co _1-xFe _xGe and Co _1-yNi _yGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT ≈ 0. 11) due to its low resistivity and large negative Seebeck coefficient (S) (- 82 V / K) at 300 K. The sign-crossover of S is observed with increasing Fe concentration. 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.

Original language	English
Article number	093902
Journal	Applied Physics Letters
Volume	100
Issue number	9
DOIs	https://doi.org/10.1063/1.3691260
Publication status	Published - 2012 Feb 27
Externally published	Yes

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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10.1063/1.3691260

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title = "Band-filling dependence of thermoelectric properties in B20-type CoGe",

abstract = "We have synthesized B20-type Co 1-xFe xGe and Co 1-yNi yGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT ≈ 0. 11) due to its low resistivity and large negative Seebeck coefficient (S) (- 82 V / K) at 300 K. The sign-crossover of S is observed with increasing Fe concentration. 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.",

author = "N. Kanazawa and Y. Onose and Y. Shiomi and S. Ishiwata and Y. Tokura",

note = "Funding Information: The authors thank M. S. Bahramy, R. Arita, K. Nakamura, S. Iguchi, H. Sakai, and T. Suzuki for enlightening discussions. This work was partly supported by Grants-In-Aid for JSPS Fellows and Scientific Research (Grant Nos. 22014003, 20340086, and 23684023) from the MEXT of Japan, and FIRST Program by the Japan Society for the Promotion of Science (JSPS).",

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doi = "10.1063/1.3691260",

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AU - Kanazawa, N.

AU - Onose, Y.

AU - Shiomi, Y.

AU - Ishiwata, S.

AU - Tokura, Y.

N1 - Funding Information: The authors thank M. S. Bahramy, R. Arita, K. Nakamura, S. Iguchi, H. Sakai, and T. Suzuki for enlightening discussions. This work was partly supported by Grants-In-Aid for JSPS Fellows and Scientific Research (Grant Nos. 22014003, 20340086, and 23684023) from the MEXT of Japan, and FIRST Program by the Japan Society for the Promotion of Science (JSPS).

PY - 2012/2/27

Y1 - 2012/2/27

N2 - We have synthesized B20-type Co 1-xFe xGe and Co 1-yNi yGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT ≈ 0. 11) due to its low resistivity and large negative Seebeck coefficient (S) (- 82 V / K) at 300 K. The sign-crossover of S is observed with increasing Fe concentration. 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.

AB - We have synthesized B20-type Co 1-xFe xGe and Co 1-yNi yGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT ≈ 0. 11) due to its low resistivity and large negative Seebeck coefficient (S) (- 82 V / K) at 300 K. The sign-crossover of S is observed with increasing Fe concentration. 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.

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ER -

Band-filling dependence of thermoelectric properties in B20-type CoGe

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