Understanding the role and interplay of heavy-hole and light-hole valence bands in the thermoelectric properties of PbSe
Understanding the role and interplay of heavy-hole and light-hole valence bands in the thermoelectric properties of PbSe
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DOI：
10.1103/physrevb.91.085207
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发表时间：
2015-02-27
影响因子：
3.7
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
--
作者：
Chasapis, Thomas C.;Lee, Yeseul;Kanatzidis, Mercouri G.
PbSe的热电性能近年来得到了显著改善，达到了类似于1.6的优值ZT。空穴掺杂的高温热电材料PbSe的输运性质特别有趣，并且在其中起着关键作用。在这里，他们分析了广泛的温度和空穴浓度范围。实验中观察到的塞贝克系数和霍尔系数的变化的特殊功能可以占内的两个波段模型的框架。被认为是由温度依赖的能量偏移分开的两个价带。在室温下，光空穴带的极值具有类似于0.27 m（o）的态密度质量。它是非抛物线和各向异性的，可以用凯恩模型来描述。重空穴带的极值是各向同性的抛物线型，具有大得多的态密度质量，类似于2.5 m（o）。我们发现，对于重掺杂的组合物，高质量带贡献的塞贝克系数，即使在室温下。随着温度的升高，空穴从轻空穴向重空穴分支转移，产生反常的温度相关霍尔系数，在650 K附近出现峰值。对于Na掺杂的样品，对于0.01
The thermoelectric properties of PbSe have significantly improved in recent years reaching figures of merit ZT similar to 1.6. The transport properties of the hole-doped high temperature thermoelectric material PbSe are particularly interesting and play a key role in this. Here, they were analyzed over wide temperature and hole concentration ranges. The special features observed in the variation of the experimental Seebeck coefficient and Hall coefficient can be accounted for within the framework of a two-band model. Two valence bands separated by a temperature dependent energy offset are considered. The extremum of the light-hole band has a density of states mass similar to 0.27 m(o) at room temperature. It is nonparabolic and anisotropic and can be described by the Kane model. The extremum of the heavy-hole band is isotropic and parabolic with a much larger density of states mass similar to 2.5 m(o). We find that for heavily doped compositions, the high mass band contributes the Seebeck coefficient, even at room temperature. With rising temperature, holes are transferred from the light-hole to the heavy-hole branch, giving rise to the anomalous temperature dependent Hall coefficient, which is found peaked near similar to 650 K. For Na-doped samples Pb1-xNaxSe for 0.01