论文标题
双重分配对p型半手塔斯布鲁的结构稳定性和改善热电性能的影响：一项第一原理研究
Effect of Bi-substitution on Structural Stability and Improved Thermoelectric Performance of p-type Half-Heusler TaSbRu: A First-principles Study
论文作者
论文摘要
最近，Fang等人。从第一原理的1200 K中预测tasbru合金中的高ZT为1.54，而无需考虑自旋轨道相互作用，准确的电子结构，声子散射的细节以及能量依赖性的孔漏洞松弛时间。在这里，我们报告了考虑到重要参数的第一原理计算，从第一原理计算中报告了结构稳定性和热电性能的细节。这种间接的带隙半导体（例如TB-MBJ+SOC的0.8 eV）具有高度分散和退化的价频段，导致最大功率因数为300K时3.8 mWm-1k-2。由于SB-5P对带隙形成的贡献很小，因此SB位点上BI的取代不会导致电子结构发生显着变化。尽管由于带隙，电导率略有变化，sebeck系数增加了BI，因此功率因子在300K时（50％BI）降低至〜3 MW M-1K-2。另一侧，晶格导热率有效地从20 w/m k下降到5，因为BI引入了声音声子区域的显着贡献并加剧了声子散射。因此，ZT值通过BI-subStitution提高，从0.45（纯tasbru）达到1200 K时达到1.1（50％BI）。因此，本研究表明，如何改善基于SB的半赫斯勒化合物和tasbru（占BI 50％）的TE性能是高温应用的有希望的材料。
Recently, Fang et al. have predicted a high ZT of 1.54 in TaSbRu alloys at 1200 K from first-principles without considering spin-orbit interaction, accurate electronic structure, details of phonon scattering, and energy-dependent holes relaxation time. Here, we report the details of structural stability and thermoelectric performance of Bi-Substituted p-type TaSbRu from first-principles calculations considering theses important parameters. This indirect bandgap semiconductor (Eg=0.8 eV by TB-mBJ+SOC) has highly dispersive and degenerate valence bands, which lead to a maximum power factor, 3.8 mWm-1K-2 at 300K. As Sb-5p has a small contribution to the bandgap formation, the substitution of Bi on the Sb site does not cause significant change to the electronic structure. Although the Seebeck coefficient increases by Bi due to slight changes in the bandgap, electrical conductivity, and hence, the power factor reduces to ~3 mW m-1K-2 at 300K (50% Bi). On the other side, lattice thermal conductivity drops effectively to 5 from 20 W/m K as Bi introduces a significant contribution in the acoustic phonon region and intensify phonon scattering. Thus, ZT value is improved through Bi-substitution, reaching 1.1 (50% Bi) at 1200 K from 0.45 (pure TaSbRu) only. Therefore, the present study suggests how to improve the TE performance of Sb-based half-Heusler compounds and TaSbRu (with 50% Bi) is a promising material for high-temperature applications.
