The 19‐electron VCoSb compounds are actually composites of an off‐stoichiometric half‐Heusler phase and impurities. Here the compositional adjustment is systematically studied in V_1−xCoSb to obtain single‐phase V_0.955CoSb. Hall measurements suggest that such a V vacancy, as well as Ti doping, can optimize the carrier concentration, which decreases from ≈11.3 × 10²¹ cm⁻³ for VCoSb to ≈6.3 × 10²¹ cm⁻³ for V_0.755Ti_0.2CoSb. Low sound velocity contributes to the intrinsically low lattice thermal conductivity for VCoSb‐based materials. The high Ti‐dopant content results in enhanced point‐defect scattering, which further decreases the lattice thermal conductivity. Finally, the optimized n‐type V_0.855Ti_0.1CoSb is found to reach a peak ZT of ≈0.7 at 973 K. The work demonstrates that the VCoSb‐based half‐Heuslers are promising thermoelectric materials.

中文翻译：

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钛掺杂可增强带有钒空位的19电子VCoSb半霍斯勒化合物的热电性能

19电子VCoSb化合物实际上是非化学计量的半霍斯勒相和杂质的复合物。在这里，在V _{1- x} CoSb中系统地研究了组成调整，以获得单相V _0.955 CoSb。霍尔测量表明，这种V空位以及Ti掺杂可以优化载流子浓度，从VCoSb的≈11.3×10 ²¹ cm ^-3降至V _0.755 Ti _0.2的≈6.3×10 ²¹ cm ^-3。CoSb。较低的声速会导致基于VCoSb的材料固有的晶格导热率较低。Ti掺杂剂含量高会导致点缺陷散射增强，从而进一步降低晶格导热率。最后，发现优化的n型V _0.855 Ti _0.1 CoSb在973 K时的ZT峰值约为0.7。这项工作表明，基于VCoSb的半霍斯勒管是有前途的热电材料。