Fan Tao, Xie Congwei, Wang Shiyao, Oganov Artem R, Cheng Laifei
International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University Xi'an Shaanxi 710072 P. R. China
Science and Technology on Thermostructural Composite Materials Laboratory, School of Materials Science and Engineering, Northwestern Polytechnical University Xi'an Shaanxi 710072 P. R. China.
RSC Adv. 2018 May 9;8(31):17168-17175. doi: 10.1039/c8ra02436g.
MgX (X = Si, Ge, Sn) compounds are semiconductors and their solid solutions are believed to be promising mid-temperature thermoelectric materials. By contrast, MgPb is a metal and few studies have been conducted to investigate the thermoelectric properties of MgSi-MgPb solid solutions. Here, we present a theoretical study exploring whether MgPb-MgSi solid solutions can be used as thermoelectric materials or not. We firstly constructed several MgSi Pb (0 ≤ ≤ 1) structures and calculated their electronic structures. It is suggested that MgSi Pb are potential thermoelectric semiconductors in the range of 0 ≤ ≤ 0.25. We then explicitly computed the electron relaxation time and both the electronic and lattice thermal conductivities of MgSi Pb (0 ≤ ≤ 0.25) and studied the effect of Pb concentration on the Seebeck coefficient, electrical conductivity, thermal conductivity, and thermoelectric figure of merit (). At low Pb concentration ( = 1/16), the of the MgSi Pb solid solutions (up to 0.67 at 900 K) reaches a maximum and is much higher than that of MgSi.
MgX（X = Si、Ge、Sn）化合物是半导体，其固溶体被认为是很有前景的中温热电材料。相比之下，MgPb是一种金属，很少有研究对MgSi - MgPb固溶体的热电性能进行探究。在此，我们开展了一项理论研究，探索MgPb - MgSi固溶体是否可用作热电材料。我们首先构建了几种MgSiₓPb₁₋ₓ（0 ≤ x ≤ 1）结构，并计算了它们的电子结构。结果表明，在0 ≤ x ≤ 0.25范围内，MgSiₓPb₁₋ₓ是潜在的热电半导体。然后，我们明确计算了MgSiₓPb₁₋ₓ（0 ≤ x ≤ 0.25）的电子弛豫时间以及电子热导率和晶格热导率，并研究了Pb浓度对塞贝克系数、电导率、热导率和热电优值（ZT）的影响。在低Pb浓度（x = 1/16）下，MgSiₓPb₁₋ₓ固溶体的ZT（在900 K时高达0.67）达到最大值，且远高于MgSi的ZT。
