Valley anisotropy is a favorable electronic structure feature that could be utilized for good thermoelectric performance. Here, taking advantage of the single anisotropic Fermi pocket in p-type Mg₃Sb₂, a feasible strategy utilizing the valley anisotropy to enhance the thermoelectric power factor is demonstrated by synergistic studies on both single crystals and textured polycrystalline samples. Compared to the heavy-band direction, a higher carrier mobility by a factor of 3 is observed along the light-band direction, while the Seebeck coefficient remains similar. Together with lower lattice thermal conductivity, an increased room-temperature zT by a factor of 3.6 is found. Moreover, the first-principles calculations of 66 isostructural Zintl phase compounds are conducted and 9 of them are screened out displaying a p_z-orbital-dominated valence band, similar to Mg₃Sb₂. In this work, we experimentally demonstrate that valley anisotropy is an effective strategy for the enhancement of thermoelectric performance in materials with anisotropic Fermi pockets.

谷各向异性是一种有利的电子结构特征，可用于获得良好的热电性能。在这里，利用p型Mg ₃ Sb ₂中的单个各向异性费米口袋，通过对单晶和织构多晶样品的协同研究证明了利用谷各向异性来提高热电功率因数的可行策略。与重带方向相比，沿轻带方向观察到载流子迁移率提高了 3 倍，而塞贝克系数保持相似。连同较低的晶格热导率，室温zT增加了 3.6 倍。此外，还对66种同构Zintl相化合物进行了第一性原理计算，筛选出9种类似Mg ₃ Sb ₂的p _z轨道主导价带化合物。在这项工作中，我们通过实验证明谷各向异性是增强具有各向异性费米袋材料热电性能的有效策略。