通过Wannier轨道分析了解基于Mg2Si的系统中的能带工程,Annalen Der Physik

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通过Wannier轨道分析了解基于Mg2Si的系统中的能带工程
Annalen Der Physik ( IF 2.2 ) Pub Date : 2020-05-07 , DOI: 10.1002/andp.201900543
Xiaojian Tan _{1,

2} , Yinong Yin ₁ , Haoyang Hu ₁ , Yukun Xiao ₁ , Zhe Guo _{1,

2} , Qiang Zhang _{1,

2} , Hongxiang Wang _{1,

2} , Guo‐Qiang Liu _{1,

2} , Jun Jiang _{1,

2}

Affiliation

Mg ₂ Si

_{1个 - X}

Sn _x固溶体是能带工程最有代表性的例子之一，其中热导性能通过导带会聚而得到显着改善。Si和Sn之间的化学差异可以简单地解释其背后的机理。在此基于Wannier函数分析的系统理论研究报告。结果表明，Mg ₂ Si中的能带会聚

_{1个 - X}

Sn _x实际上是由晶格常数的变化驱动的，因为重的和轻的传导谷对键合长度的依赖性不同。或者，也可以通过引入阳离子掺杂剂直接调节两个化学键的相对强度来实现能带工程。镁

_{2 - X}

Sr _x Si，类似于Mg ₂ Si的能带收敛

_{1个 - X}

Sn _x由能带结构计算预测。这项工作使人们对Mg ₂ Si基材料的能带收敛有了深刻的了解，并为实验研究提供了更加有效和丰富的设计。

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Understanding the Band Engineering in Mg2Si‐Based Systems from Wannier‐Orbital Analysis

The Mg₂Si

_{1 - x}

Sn_x solid 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 Mg₂Si

_{1 - x}

Sn_x is 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 Mg

_{2 - x}

Sr_xSi, a similar band convergence to Mg₂Si

_{1 - x}

Sn_x is 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.

更新日期：2020-05-07

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