Band engineering and improved thermoelectric performance in M-doped SnTe (M = Mg, Mn, Cd, and Hg).
Band engineering and improved thermoelectric performance in M-doped SnTe (M = Mg, Mn, Cd, and Hg).
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DOI：
10.1039/c5cp07620j
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
X. Tan;H. Shao;J. He;G. Q. Liu;J. Xu;J. Jiang;H. C. Jiang
中科院分区：
文献类型：
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作者：
X. Tan;H. Shao;J. He;G. Q. Liu;J. Xu;J. Jiang;H. C. Jiang
用包括自旋-轨道耦合在内的第一性原理计算方法研究了M掺杂SNTE(M=Mg，Mn，Cd和Hg)的电子结构。结果表明，锡空位在SNTE的能带工程中起着重要的作用，表现出与其相关化合物PbTe不同的性质。两个价带间的带隙变大，能隙减小，与实验测量结果吻合较好。这两个带的修正都导致了Seebeck系数的增加，这在随后的Boltzmann输运计算中得到了明确的证实。在较宽的载流子浓度范围内，计算的掺锰SNTE的Seebeck系数与实验数据符合得很好。由于Seebeck系数的提高，掺Mn和掺Cd的SNTE在800K附近表现出良好的热电性能，ZT分别为1.32和1.65。
The electronic structures of M-doped SnTe (M = Mg, Mn, Cd, and Hg) are investigated by using first-principles calculations including spin-orbit coupling. It is found that Sn vacancy plays an important role in the band engineering of SnTe, showing a different property from its related compound PbTe. The enlarged band gap and reduced energy separation between two valence bands are in good agreement with experimental measurements. Both of the two band modifications lead to the increase of Seebeck coefficients, which is explicitly confirmed by the followed Boltzmann transport calculations. The calculated Seebeck coefficients for Mn-doped SnTe agree well with the experimental data in a broad range of carrier concentration. Owing to the improved Seebeck coefficients, Mn- and Cd-doped SnTe exhibit promising thermoelectric properties with ZT = 1.32 and 1.65 at around 800 K, respectively.