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arXiv 1409.4496cond-mat.mtrl-sci
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Cu $_3$ SbSe $_4$中缺陷的理论研究:寻找提高热电性能的最佳掺杂剂

Theoretical Study of Defects in Cu$_3$SbSe$_4$: Search for Optimum Dopants for Enhancing Thermoelectric Properties

Dat T. Do, S. D. Manhanti

摘要:

Cu $_3$ SbSe $_4$由于在300 K及更高温度下的高热电势($>400\ μ$ V/K)而成为一种很有前途的热电材料。虽然它有一个简单的晶体结构,从锌铌结构,以前的工作表明,带隙形成的物理是相当微妙的,由于积极的孤对(5 $s^2$)的Sb和非本地交换这些和硒5 $p$电子之间的相互作用的重要性。由于对于任何应用的半导体理解的缺陷的性质是必不可少的,我们讨论了几个点缺陷的Cu $_3$ SbSe $_4$,包括空位和替换的每个组件的系统研究的结果。利用密度泛函理论的第一性原理计算表明,在各种可能的掺杂剂中,$p$型掺杂可以通过用包括Sn、Ge、Pb和Ti的$IV$族元素取代Sb来实现,而$n$型掺杂可以通过用Mg、Zn取代Cu来实现。在Se位点掺杂似乎相当困难。电子结构计算还表明在名义上纯的Cu $_3$ SbSe $_4$中看到的$p$型行为最有可能是由于Cu空位而不是Se空位。

英文摘要:

Cu$_3$SbSe$_4$ is a promising thermoelectric material due to high thermopower ($>400\ μ$V/K) at 300K and higher. Although it has a simple crystal structure derived from zinc blende structure, previous work has shown that the physics of band gap formation is quite subtle due to the importance of active lone pair (5$s^2$) of Sb and the non-local exchange interaction between these and Se 5$p$ electrons. Since for any application of semiconductors understanding the properties of defects is essential, we discuss the results of a systematic study of several point defects in Cu$_3$SbSe$_4$ including vacancies and substitutions for each of the components. First principles calculations using density functional theory show that among variety of possible dopants, $p$-type doping can be done by substituting Sb with group $IV$ elements including Sn, Ge, Pb and Ti and $n$-type doping can be done by replacing Cu by Mg, Zn. Doping at the Se site appears to be rather difficult. Electronic structure calculations also suggest that the $p$-type behavior seen in nominally pure Cu$_3$SbSe$_4$ is most likely due to Cu vacancy rather than Se vacancy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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