论文标题
对高效热电半身化合物的高吞吐量搜索
A high throughput search of efficient thermoelectric half-Heusler compounds
论文作者
论文摘要
半身勒化合物已成为有希望的热电材料，提供了巨大的组成空间来调整其热电性能。一类稳定的半助母子化合物是由周期表中三个特定组的元素形成的。 X$_{p}$X$'_{1-p}$Y$_{q}$Y$'_{1-q}$Z$_{r}$Z$'_{1-r}$ (with X, X$'$= Ti, Zr, Hf, Y, Y$'$ = Ni, Pd, Pt and Z, Z$'$ = Ge, Sn, Pb and p, Q，r = 0、0.25、0.75和1）分别研究了X，Y和Z位点的各种化学计量学元素取代。智能过滤器在我们高通量密度功能理论计算的每个步骤中都采用，以过滤具有提高功绩的化合物。在确认了几个已知结果的同时，计算还揭示了改善化合物类热电性能的未知途径。 The 50% X as well as Z site substitution of the parent Heusler individually are found to marginally enhance the power factor for both the $p$- and $n$-type doping, while leading to considerable enhancement in the figure of merit (by $\sim$24 %) specifically due to lowering of the lattice thermal conductivity because of increase in lattice disorder in approximately the same cell volume.此外，本研究证实了实验方案，y站点的替代不会导致功率归因器的增强，因为在高对称点处的频带退化性破坏了。这项工作将作为与该化合物类别合作的实验主义者的合并成本有效指南，以增强构图的功绩。
Half-Heusler compounds have emerged as promising thermoelectric materials that offer huge compositional space to tune their thermoelectric performance. A class of stable half Heusler compounds formed from elements of three specific groups in the periodic table viz. X$_{p}$X$'_{1-p}$Y$_{q}$Y$'_{1-q}$Z$_{r}$Z$'_{1-r}$ (with X, X$'$= Ti, Zr, Hf, Y, Y$'$ = Ni, Pd, Pt and Z, Z$'$ = Ge, Sn, Pb and p, q, r = 0, 0.25, 0.75 and 1) via various stoichiometric isoelectronic elemental substitution at the X, Y and Z sites respectively is investigated. Intelligent filters are employed at each step of our high throughput density functional theory calculations to filter compounds with improved figure of merit. While confirming several known results, the calculations also reveal unknown pathways to improve the thermoelectric performance of the compound class. The 50% X as well as Z site substitution of the parent Heusler individually are found to marginally enhance the power factor for both the $p$- and $n$-type doping, while leading to considerable enhancement in the figure of merit (by $\sim$24 %) specifically due to lowering of the lattice thermal conductivity because of increase in lattice disorder in approximately the same cell volume. Furthermore, the present study confirms the experimental scenario that Y site substitution does not lead to enhancement of the powerfactor because of the breaking of band degeneracies at the high symmetry points. This work will serve as a consolidated cost effective guideline for experimentalist working with this compound class on enhancing the powerfactor and figure of merit of the compositions.
