Direct observation of double valence-band extrema and anisotropic effective masses of the thermoelectric material SnSe
Direct observation of double valence-band extrema and anisotropic effective masses of the thermoelectric material SnSe
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DOI：
10.7567/jjap.57.010301
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发表时间：
2017-12
影响因子：
1.5
通讯作者：
T. Nagayama;K. Terashima;T. Wakita;H. Fujiwara;T. Fukura;Y. Yano;K. Ono;H. Kumigashira;
中科院分区：
文献类型：
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作者：
T. Nagayama;K. Terashima;T. Wakita;H. Fujiwara;T. Fukura;Y. Yano;K. Ono;H. Kumigashira;
利用同步辐射角分辨光电子能谱研究了层状锡硒的电子结构。我们观察到，价带顶部由两个几乎独立的空穴带组成，其顶部的能量相差0.20 meV，这表明有必要采用多通道模型来描述热电性质。估计的有效质量是各向异性的，面内值为0.16-0.39 m0，面外值为0.71 m0，其中m0是静止电子质量。电子结构的信息对于进一步提高空穴掺杂SnSe的热电性能是必不可少的。
Synchrotron-based angle-resolved photoemission spectroscopy is used to determine the electronic structure of layered SnSe, which was recently turned out to be a potential thermoelectric material. We observe that the top of the valence band consists of two nearly independent hole bands, whose tops differ by ∼20 meV in energy, indicating the necessity of a multivalley model to describe the thermoelectric properties. The estimated effective masses are anisotropic, with in-plane values of 0.16–0.39 m0 and an out-of-plane value of 0.71 m0, where m0 is the rest electron mass. Information of the electronic structure is essential to further enhance the thermoelectric performance of hole-doped SnSe.