arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.12324cond-mat.mtrl-sci
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低晶格热导率半赫斯勒化合物BiBaK的高热电性能

High thermoelectric performance of half-Heusler compound BiBaK with intrinsically low lattice thermal conductivity

S. H. Han, Z. Z. Zhou, C. Y. Sheng, J. H. Liu, L. Wang, H. M. Yuan, H. J. Liu

摘要:

半赫斯勒化合物通常表现出相对较高的晶格热导率,这对于热电应用是不期望的。在这里,我们证明了第一性原理计算和玻尔兹曼输运理论的BiBaK系统是一个例外,它具有相当低的热导率证明了非常小的声子群速度和弛豫时间。详细的分析表明,重Bi和Ba原子形成笼状结构,轻K原子在笼状结构中以较大的原子位移参数晃动。结合其良好的电子输运性质,BiBaK在900 K时显示出最大的n型ZT值为1.9,这优于大多数半赫斯勒热电材料。

英文摘要:

Half-Heusler compounds usually exhibit relatively higher lattice thermal conductivity that is undesirable for thermoelectric applications. Here we demonstrate by first-principles calculations and Boltzmann transport theory that the BiBaK system is an exception, which has rather low thermal conductivity as evidenced by very small phonon group velocity and relaxation time. Detailed analysis indicates that the heavy Bi and Ba atoms form a cage-like structure, inside which the light K atom rattles with larger atomic displacement parameters. In combination with its good electronic transport properties, the BiBaK shows a maximum n-type ZT value of 1.9 at 900 K, which outperforms most half-Heusler thermoelectric materials.

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