p-type CaMg₂Sb₂ has not been favorably considered a promising thermoelectric material in comparison to other Zintl phases. However, a series of meticulously designed tactics is successfully implemented here to analyze and improve the thermoelectric performance of a CaMg₂Sb₂-based material. Band structure calculations show that the pristine CaMg₂Sb₂ has a wide indirect band gap of ≈1.11 eV, which results in its less optimal carrier concentration. To improve its consequently inferior thermoelectric performance, Na doping is first deployed to increase the carrier concentration to an optimal level. Subsequently, the ideal bandwidth and enhanced carrier mobility are simultaneously obtained through Zn alloying. Finally, partial Yb substitution for Ca effectively restrains the bipolar effect in this CaMg₂Sb₂-based material and augments its power factor while suppressing its lattice thermal conductivity to a minimum. As a result, a 20-fold-higher peak figure of merit (zT) of ≈0.85 at 773 K and an average zT value of ≈0.50 from 298 to 773 K are achieved in Ca_0.69Yb_0.3Na_0.01Mg_1.1Zn_0.9Sb₂, the highest for both values among all [Ca,Mg,Eu,Yb]Mg₂Sb₂-based materials reported to date. Furthermore, such a combination of rationally designed tactics as proposed here may assist in exploring the improvement of other thermoelectric materials that have long been overlooked.

中文翻译：

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提高 CaMg2Sb2 基 p 型材料热电性能的组合策略

与其他 Zintl 相相比，p 型 CaMg ₂ Sb _{2未被认为是有前途的热电材料。}然而，这里成功地实施了一系列精心设计的策略来分析和提高 CaMg ₂ Sb ₂基材料的热电性能。能带结构计算表明，原始 CaMg ₂ Sb ₂具有≈1.11 eV的宽间接带隙，这导致其不太理想的载流子浓度。为了改善其较差的热电性能，首先采用钠掺杂将载流子浓度提高到最佳水平。随后，通过锌合金化同时获得了理想的带宽和增强的载流子迁移率。最后，部分Yb替代Ca有效地抑制了这种CaMg ₂ Sb ₂基材料中的双极效应并增加了其功率因数，同时将其晶格热导率抑制到最低限度。结果，在 Ca _{0.69中实现了 20 倍的峰值品质因数 (} zT ) 在 773 K 时约为 0.85，从 298 到 773 K 的平均zT值约为 0.50Yb _0.3 Na _0.01 Mg _1.1 Zn _0.9 Sb ₂ ，在迄今为止报道的所有[Ca,Mg,Eu,Yb]Mg ₂ Sb ₂基材料中这两个值的最高值。此外，本文提出的这种合理设计策略的组合可能有助于探索其他长期以来被忽视的热电材料的改进。