Evaluation of Half‐Heusler Compounds as Thermoelectric Materials Based on the Calculated Electrical Transport Properties
Evaluation of Half‐Heusler Compounds as Thermoelectric Materials Based on the Calculated Electrical Transport Properties
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DOI：
10.1002/adfm.200701369
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发表时间：
2008-10
影响因子：
19
通讯作者：
Jiong Yang;Huanming Li;Ting Wu;Wenqing Zhang;Lidong Chen;Jihui Yang
中科院分区：
文献类型：
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作者：
Jiong Yang;Huanming Li;Ting Wu;Wenqing Zhang;Lidong Chen;Jihui Yang
本文对从100多个半-Heusler(HH)化合物中筛选出的36个HH化合物的热电相关电输运性质进行了理论评价。在电荷载流子的常弛豫时间近似下，用从头计算和Boltzmann输运方程研究了该体系的电子结构和电输运性质。电子结构结果预测了这些HH化合物的带隙，并表明许多HHS是窄禁带半导体，因此是潜在的良好的热电材料。研究了Seebeck系数、电导率和功率因数与费米能级的关系。计算了与材料热电性能相关的最大功率因数和相应的最佳p型或n型掺杂水平，为实验工作提供了一定的指导。对于某些HH体系，估算的最佳掺杂能级和Seebeck系数与测量结果吻合较好。根据我们的计算，几种HHS被推荐为潜在的良好的热电材料。
A theoretical evaluation of the thermoelectric‐related electrical transport properties of 36 half‐Heusler (HH) compounds, selected from more than 100 HHs, is carried out in this paper. The electronic structures and electrical transport properties are studied using ab initio calculations and the Boltzmann transport equation under the constant relaxation time approximation for charge carriers. The electronic structure results predict the band gaps of these HH compounds, and show that many HHs are narrow‐band‐gap semiconductors and, therefore, are potentially good thermoelectric materials. The dependence of Seebeck coefficient, electrical conductivity, and power factor on the Fermi level is investigated. Maximum power factors and the corresponding optimal p‐ or n‐type doping levels, related to the thermoelectric performance of materials, are calculated for all HH compounds investigated, which certainly provide guidance to experimental work. The estimated optimal doping levels and Seebeck coefficients show reasonable agreement with the measured results for some HH systems. A few HHs are recommended to be potentially good thermoelectric materials based on our calculations.