Zhu Jianbo, Liu Ming, Dong Xingyan, Li Jingyu, Liu Peng-Fei, Chen Xin, Liu Zihang, Zhang Yongsheng, Guo Fengkai, Sui Jiehe
State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin 150001, China.
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
Natl Sci Rev. 2025 May 31;12(8):nwaf216. doi: 10.1093/nsr/nwaf216. eCollection 2025 Aug.
Thermoelectric materials are advanced functional semiconductors for the forthcoming era of energy conversion. The development in this field critically depends on the understanding of their band structures. However, many analyses rely on the parabolic band model that oversimplifies the realistic electron behavior. Such simplification leads to significant deviations in the predicted behavior of electrical transport properties due to the non-local characteristics of the Seebeck coefficient and the Lorenz number. This study introduces a nonparabolicity factor , which quantitatively measures the deviations from parabolic dispersion in semiconductor band structures and can also directly predict the thermoelectric performance change induced by the band nonparabolicity. Notably, our results reveal that the influence of band nonparabolicity is significant when estimating the Lorenz number. We have formulated a universal modified solution for the Lorenz number, which can effectively correct the non-physical lattice thermal conductivity derived from the typical parabolic band model in various representative thermoelectric semiconductors, establishing a basis for further insights into the underlying mechanisms of electrical and thermal transport.
热电材料是面向即将到来的能量转换时代的先进功能半导体。该领域的发展严重依赖于对其能带结构的理解。然而，许多分析依赖于抛物线能带模型，该模型过度简化了实际的电子行为。由于塞贝克系数和洛伦兹数的非局部特性，这种简化导致了电输运性质预测行为的显著偏差。本研究引入了一个非抛物线因子，它定量地测量半导体能带结构中与抛物线色散的偏差，并且还可以直接预测由能带非抛物线性引起的热电性能变化。值得注意的是，我们的结果表明，在估计洛伦兹数时，能带非抛物线性的影响是显著的。我们为洛伦兹数制定了一个通用的修正解，它可以有效地校正各种代表性热电半导体中由典型抛物线能带模型得出的非物理晶格热导率，为进一步深入了解电输运和热输运的潜在机制奠定了基础。
