College of Science, Zhengzhou Key Laboratory of Low-dimensional Quantum Materials and Devices, Zhongyuan University of Technology, Zhengzhou 450007, China.
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Phys Chem Chem Phys. 2022 Dec 14;24(48):29693-29699. doi: 10.1039/d2cp04167g.
The bilayer SnP is recently predicted to exfoliate from its bulk phase, and motivated by the transition of the metal-to-semiconductor when the bulk SnP is converted to the bilayer, we study the thermoelectric performance of the bilayer SnP using first-principles combined with Boltzmann transport theory and deformation potential theory. The results indicate that the bilayer SnP is an indirect band gap semiconductor and possesses high carrier mobility. The high carrier mobility results in a large Seebeck coefficient observed in both n- and p-doped bilayer SnP, which is helpful for acquiring a high figure of merit (). Moreover, by analyzing the phonon spectrum, relaxation time, and joint density of states, we found that strong phonon scattering makes the phonon thermal conductivity extremely low (∼0.8 W m K at room temperature). Together with a high power factor and a low phonon thermal conductivity, the maximum value can reach up to 3.8 for p-type doping at a reasonable carrier concentration, which is not only superior to that of the monolayer SnP, but also that of the excellent thermoelectric material SnSe. Our results shed light on the fact that bilayer SnP is a promising thermoelectric material with a better performance than its monolayer phase.
双层 SnP 最近被预测可以从其体相中剥离出来，并且受到当体相 SnP 转化为双层时金属到半导体的转变的启发，我们使用第一性原理结合玻尔兹曼输运理论和变形势理论研究了双层 SnP 的热电性能。结果表明，双层 SnP 是一种间接带隙半导体，具有较高的载流子迁移率。高载流子迁移率导致在 n 型和 p 型掺杂双层 SnP 中都观察到较大的 Seebeck 系数，这有助于获得高品质因数 ( )。此外，通过分析声子谱、弛豫时间和联合态密度，我们发现强声子散射使声子热导率极低（室温下约为 0.8 W m K）。与高功率因子和低声子热导率相结合，在合理的载流子浓度下，p 型掺杂的最大 值可达 3.8，不仅优于单层 SnP，也优于优异的热电材料 SnSe。我们的结果表明，双层 SnP 是一种很有前途的热电材料，其性能优于其单层相。
