Mg₃Sb₂ as a Zintl compound is a promising thermoelectric material with the intrinsically low lattice thermal conductivity and excellent n-type electrical properties, but its p-type electrical transport properties are poor. Here, the thermoelectric performance of Mg₃Sb₂ under the effect of biaxial strain is investigated by using first-principles method and Boltzmann transport theory. The application of biaxial strain enables tuning the band structure of Mg₃Sb₂ in such a way that the band degeneracy of both the conduction band and valence band increases. As the biaxial strain increases, the Seebeck coefficient of p-type Mg₃Sb₂ has a remarkable increase, leading to a significant improvement in power factor. This is mainly ascribed to the achievement of valence band orbital degeneracy. Meanwhile, the lattice thermal conductivity exhibits very slight biaxial strain dependence within the strain range considered in this work, which increases from 1.28 to 1.62 W m⁻¹ K⁻¹ at 300 K. Finally, the highest ZT of p-type Mg₃Sb₂ at 700 K can be up to 2.6 along the in-plane direction under −2.5% biaxial strain, which is almost three times that of the unstrained counterpart. The realization of high thermoelectric performance of p-type Mg₃Sb₂ will promote its practical applications as thermoelectric generators.

Mg ₃ Sb ₂作为Zintl化合物是一种很有前途的热电材料，具有固有的低晶格热导率和优异的n型电性能，但其p型电传输性能较差。在此，利用第一性原理方法和玻尔兹曼输运理论研究了Mg ₃ Sb _{2在双轴应变作用下的热电性能。}双轴应变的应用能够调整Mg ₃ Sb ₂的能带结构，使得导带和价带的能带简并性增加。随着双轴应变的增加，p 型 Mg ₃ Sb _{2的塞贝克系数}显着增加，导致功率因数显着提高。这主要归因于价带轨道简并的实现。同时，晶格热导率在本工作考虑的应变范围内表现出非常轻微的双轴应变依赖性，在 300 K 时从 1.28 W m -1 K -1 增加到 1.62 W m ^-1  K ^-1 。最后， p 型 Mg ₃ Sb的最高ZT在 -2.5% 双轴应变下，700 K 时的₂沿面内方向可高达 2.6，几乎是未应变对应物的三倍。p型Mg ₃ Sb _{2高热电性能的实现}将促进其作为热电发电机的实际应用。