Band-filling dependence of thermoelectric properties in B20-type CoGe
Band-filling dependence of thermoelectric properties in B20-type CoGe
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DOI：
10.1063/1.3691260
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发表时间：
2012-02-27
影响因子：
4
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Kanazawa, N.;Onose, Y.;Tokura, Y.
我们采用高压法合成了B20型的Co1-xFexGe和Co1-yNiyGe，并研究了它们的热电性能与能带填充的关系。CoGe由于其低电阻率和在300 K下大的负Seebeck系数（S）（82 μ V/K）而显示出大的品质因数（ZT约为0.11）。随着Fe浓度的增加，观察到S的符号交叉。玻尔兹曼输运模型可以半定量地解释实验结果，由此我们得出结论：大的正或负S起源于狄拉克锥和费米能附近急剧弯曲的平带组成的非对称带结构。(C)2012年美国物理学会。[http：//dx.doi.org/10.1063/1.3691260]
We have synthesized B20-type Co1-xFexGe and Co1-yNiyGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT approximate to 0.11) due to its low resistivity and large negative Seebeck coefficient (S) ( 82 mu 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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691260]