Chen Shao-Bo, Liu Gang, Yan Wan-Jun, Hu Cui-E, Chen Xiang-Rong, Geng Hua-Yun
College of Physics, Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610064, China.
College of Electronic and Information Engineering, Anshun University, Anshun 561000, China.
Nanomaterials (Basel). 2021 Dec 23;12(1):40. doi: 10.3390/nano12010040.
Thermoelectric (TE) materials can convert waste heat into electrical energy, which has attracted great interest in recent years. In this paper, the effect of biaxial-tensile strain on the electronic properties, lattice thermal conductivity, and thermoelectric performance of -phase SeTe and SeTe monolayers are calculated based on density-functional theory and the semiclassical Boltzmann theory. The calculated results show that the tensile strain reduces the bandgap because the bond length between atoms enlarges. Moreover, the tensile strain strengthens the scatting rate while it weakens the group velocity and softens the phonon model, leading to lower lattice thermal conductivity . Simultaneously, combined with the weakened , the tensile strain can also effectively modulate the electronic transport coefficients, such as the electronic conductivity, Seebeck coefficient, and electronic thermal conductivity, to greatly enhance the value. In particular, the maximum n-type doping under 1% and 3% strain increases up to six and five times higher than the corresponding without strain for the SeTe and SeTe monolayers, respectively. Our calculations indicated that the tensile strain can effectively enhance the thermoelectric efficiency of SeTe and SeTe monolayers and they have great potential as TE materials.
热电（TE）材料能够将废热转化为电能，近年来已引起了人们的极大兴趣。本文基于密度泛函理论和半经典玻尔兹曼理论，计算了双轴拉伸应变对β相SeTe和SeTe单层的电子性质、晶格热导率和热电性能的影响。计算结果表明，拉伸应变会减小带隙，这是因为原子间的键长增大。此外，拉伸应变会增强散射率，同时减弱群速度并软化声子模型，从而导致较低的晶格热导率。同时，结合减弱的晶格热导率，拉伸应变还能有效调节电子输运系数，如电导率、塞贝克系数和电子热导率，从而大幅提高ZT值。特别是，对于SeTe和SeTe单层，在1%和3%应变下的最大n型掺杂分别比相应的无应变时提高了六倍和五倍。我们的计算表明，拉伸应变能够有效提高SeTe和SeTe单层的热电效率，它们作为热电材料具有巨大潜力。
