Chen ShaoBo, Tao Wang-Li, Zhou Yu, Zeng Zhao-Yi, Chen Xiang-Rong, Geng Hua-Yun
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People's Republic of China.
College of Electronic and Information Engineering, Anshun University, Anshun 561000, People's Republic of China.
Nanotechnology. 2021 Aug 19;32(45). doi: 10.1088/1361-6528/ac1a91.
The design and search for efficient thermoelectric materials that can directly convert waste heat into electricity have been of great interest in recent years since they have practical applications in overcoming the challenges of global warming and the energy crisis. In this work, two new two-dimensional 1T-phase group-VI binary compounds SeTe and SeTewith outstanding thermoelectric performances are predicted using first-principles calculations combined with Boltzmann transport theory. The dynamic stability is confirmed based on phonon dispersion. It is found that the spin-orbit coupling effect has a significant impact on the band structure of SeTe, and induces a transformation from indirect to direct band gap. The electronic and phononic transport properties of the SeTe and SeTemonolayer are calculated and discussed. High carrier mobility (up to 3744.321 and 2295.413 cmVSfor electron and hole, respectively) is exhibited, suggesting great applications in nanoelectronic devices. Furthermore, the maximum thermoelectric figure of meritof SeTefor n-type and p-type is 2.88, 1.99 and 5.94, 3.60 at 300 K and 600 K, respectively, which is larger than that of most reported 2D thermoelectric materials. The surprising thermoelectric properties arise from the ultralow lattice thermal conductivity(0.25 and 1.89 W mKfor SeTeand SeTe at 300 K), and the origin of ultralow lattice thermal conductivity is revealed. The present results suggest that 1T-phase SeTe and SeTemonolayer are promising candidates for thermoelectric applications.
近年来，设计和寻找能够将废热直接转化为电能的高效热电材料备受关注，因为它们在应对全球变暖和能源危机挑战方面具有实际应用价值。在这项工作中，结合玻尔兹曼输运理论，利用第一性原理计算预测了两种具有优异热电性能的新型二维1T相-VI族二元化合物硒碲（SeTe）和硒碲钨（SeTeW）。基于声子色散确认了其动力学稳定性。发现自旋轨道耦合效应对SeTe的能带结构有显著影响，并导致其从间接带隙转变为直接带隙。计算并讨论了SeTe和SeTe单层的电子和声子输运性质。结果表明它们具有高载流子迁移率（电子和空穴分别高达3744.321和2295.413 cm²V⁻¹s⁻¹），这表明它们在纳米电子器件中有很大的应用潜力。此外，SeTe在300 K和600 K时，n型和p型的最大热电优值分别为2.88、1.99和5.94、3.60，大于大多数已报道的二维热电材料。其令人惊讶的热电性能源于超低的晶格热导率（SeTe和SeTe在300 K时分别为0.25和1.89 W m⁻¹K⁻¹），并揭示了超低晶格热导率的起源。目前的结果表明，1T相SeTe和SeTe单层是热电应用的有前途的候选材料。
