Understanding the band engineering in Mg2Si-based systems from Wannier-orbital analysis
Understanding the band engineering in Mg2Si-based systems from Wannier-orbital analysis
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从 Wannier 轨道分析了解 Mg2Si 基系统中的能带工程
DOI：
10.1002/andp.201900543
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Jun Jiang
中科院分区：
文献类型：
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作者：
Xiaojian Tan;Yinong Yin;Haoyang Hu;Yukun Xiao;Zhe Guo;Qiang Zhang;Hongxiang Wang;Guo-Qiang Liu;Jun Jiang
Mg_2SiSnx固溶体是能带工程中最具代表性的例子之一，它的导带收敛显著改善了材料的热电性能。其背后的机制简单地解释为硅和锡之间的化学差异。本文以Wannier函数分析为基础进行了系统的理论研究。结果表明，由于重电导谷和轻电导谷对键长的依赖程度不同，因此能带会聚实际上是由晶格常数的变化所驱动的。或者，也可以通过引入阳离子掺杂剂来直接调节两个化学键的相对强度来实现能带工程。通过能带结构计算，预测到了与Mg2SiSnx类似的能带收敛。这项工作提供了对镁硅基材料中能带会聚的深刻理解，并为实验研究提供了更有效和更丰富的设计。
The Mg2SiSnxsolid solution is one of the most representative examples of band engineering, in which the thermoelectric performance is significantly improved by the conduction band convergence. The mechanism behind it is simply explained by the chemical differences between Si and Sn. Here a systematically theoretical study is reported based on Wannier function analysis. It is revealed that the band convergence in Mg2SiSnxis actually driven by the variation of lattice constant, since the heavy and light conduction valleys have different dependence on the bonding length. Alternatively, the band engineering can also be achieved by introducing cation dopants to tune the relative strength of the two chemical bonds directly. In MgSrxSi, a similar band convergence to Mg2SiSnxis predicted by the band structure calculations. This work provides an insightful understanding of the band convergence in Mg2Si‐based materials, and it enables a more efficient and plentiful design for experimental studies.