First-principles-aided evaluation of the Nernst coefficient beyond the constant relaxation time approximation
First-principles-aided evaluation of the Nernst coefficient beyond the constant relaxation time approximation
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DOI：
10.1016/j.commatsci.2023.112193
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发表时间：
2023-06
影响因子：
3.3
通讯作者：
S. E. Rezaei;M. Zebarjadi;K. Esfarjani
中科院分区：
文献类型：
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作者：
S. E. Rezaei;M. Zebarjadi;K. Esfarjani
玻尔兹曼输运方程 (BTE) 在开路电压条件下以及同时施加磁场和温度梯度的情况下的解会产生所谓的电子能斯特响应。使用第一性原理计算作为 Boltzwann 代码的扩展并在弱磁场下有效的琼斯-齐纳展开下计算能斯特系数一直是我们之前工作的主题，该工作为能斯特效应的计算提供了通用框架，但由于使用恒定弛豫时间近似而无法捕获实验结果。与对弛豫时间的细节不敏感的塞贝克系数相反，能斯特系数与载流子迁移率成正比，因此受弛豫时间的影响很大。在这项工作中，我们重点关注在我们的形式主义中包含能量相关的电子声子和电子杂质弛豫时间。利用发达的形式主义，我们成功地再现了几个样品的实验数据。在本文中，我们报告了 Ge、Si 和 InSb 样品的结果。然而，该代码并不限于报告的样本，并且支持广泛的材料。
The solution of the Boltzmann Transport Equation (BTE) under open voltage conditions and in the presence of simultaneously applied magnetic field and temperature gradient results in the so-called Nernst response of the electrons. The calculation of the Nernst coefficient using first-principles calculations as an extension of the BoltzWann code and under Jones–Zener expansion valid for weak magnetic fields has been the subject of our previous work which provided a general framework for the calculation of the Nernst effect but was not able to capture the experimental results due to the constant relaxation time approximation used. In Contrast to the Seebeck coefficient which is not sensitive to the details of the relaxation times, the Nernst coefficient is proportional to the carrier mobility and hence is greatly affected by the relaxation times. In this work, we focus on the inclusion of the energy-dependent electron–phonon and the electron–impurity relaxation times in our formalism. Using the developed formalism, we successfully reproduced the experimental data of several samples. In this paper, we report our results on Ge, Si, and InSb samples. However, the code is not limited to the reported samples and supports a wide range of materials.