Abstract Recently layered silicon diphosphide (SiP2) single crystal has been successfully synthesized in the experiment. Based on the unique geometric structure and potential excellent physical properties, the thermoelectric transport performance of monolayer SiP2 is investigated by using Boltzmann transport theory combined with the first-principles calculations. Both thermal and electronic transport coefficients of monolayer SiP2 present obvious anisotropic behavior, in which the thermal conductivity and electrical conductivity in the a direction are less than those in the b direction. At 300 K, the phonon thermal conductivity in the a and b direction are 2.22 and 16.23 W/mK, respectively. However, the Seebeck coefficient of monolayer SiP2 is almost isotropic. Its values at room temperature could approach 3.02 mV/K and 3.15 mV/K in the a and b direction, respectively. By using the electron relaxation time calculated from the deformation potential theory, the thermoelectric figure of merit of 0.90 and 0.74 along the b- and a-axis at 300 K are obtained, respectively. The results presented in this work indicate that monolayer SiP2 processes fascinating thermoelectric performance, and foreshadow the great potential in future thermoelectric applications.

中文翻译：

---

来自第一性原理计算的潜在热电候选单层二磷化硅 (SiP2)

摘要 近年来，实验成功合成了层状二磷化硅（SiP2）单晶。基于其独特的几何结构和潜在的优异物理性能，利用玻尔兹曼传输理论结合第一性原理计算研究了单层SiP2的热电传输性能。单层SiP2的热和电子传输系数均表现出明显的各向异性行为，其中a方向的热导率和电导率小于b方向的热导率和电导率。在 300 K 时，a 和 b 方向的声子热导率分别为 2.22 和 16.23 W/mK。然而，单层SiP2的塞贝克系数几乎是各向同性的。它在室温下的值可以接近 3.02 mV/K 和 3。a 和 b 方向分别为 15 mV/K。通过使用由变形势理论计算的电子弛豫时间，分别获得了在 300 K 时沿 b 轴和 a 轴的 0.90 和 0.74 的热电品质因数。这项工作中提出的结果表明，单层 SiP2 工艺具有迷人的热电性能，并预示着未来热电应用的巨大潜力。