Wei Junhong, Guo Yongliang, Wang Guangtao
School of Science, Henan Institute of Technology Xinxiang 453003 China
School of Physics, Henan Normal University Xinxiang 453007 China
RSC Adv. 2024 Jan 2;14(1):463-477. doi: 10.1039/d3ra07345a.
In this study, using density functional and Boltzmann transport theories, we systematically investigated the effects of tensile and compressive strains on the elastic properties, phonon dispersion relation, electronic structure, and transport properties of the half-Heusler compound BiBaK. We calculated the elastic constants and phonon dispersion curves for BiBaK, which demonstrated its mechanical and thermodynamic stability, respectively, under different isotropic strains. Further, calculations showed that the electronic structure and energy bandgap of BiBaK changed with the application of isotropic strain. A high power factor and low thermal conductivity are key to improving the performance of thermoelectric materials. The figure of merit of BiBaK is 0.6 when it is unstrained and reaches a maximum value of 0.93 at -9% compressive strain and a temperature of 1200 K, indicating that under isotropic compressive strain, BiBaK compounds are efficient thermoelectric materials for high-temperature applications.
在本研究中，我们运用密度泛函理论和玻尔兹曼输运理论，系统地研究了拉伸应变和压缩应变对半赫斯勒化合物BiBaK的弹性性质、声子色散关系、电子结构及输运性质的影响。我们计算了BiBaK的弹性常数和声子色散曲线，结果分别表明了其在不同各向同性应变下的力学稳定性和热动力学稳定性。此外，计算结果显示，BiBaK的电子结构和能带隙会随着各向同性应变的施加而发生变化。高功率因数和低导热率是提高热电材料性能的关键。BiBaK在无应变时的品质因数为0.6，在-9%的压缩应变和1200 K的温度下达到最大值0.93，这表明在各向同性压缩应变下，BiBaK化合物是适用于高温应用的高效热电材料。
