High-throughput exploration of alloying as design strategy for thermoelectrics
High-throughput exploration of alloying as design strategy for thermoelectrics
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DOI：
10.1103/physrevb.92.085205
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发表时间：
2015-08-27
影响因子：
3.7
通讯作者：
Madsen, Georg K. H.
中科院分区：
文献类型：
--
作者：
Bhattacharya, Sandip;Madsen, Georg K. H.
我们探索一种材料设计策略来优化热电功率因数。该方法基于在受控体积变化时筛选能带结构变化。该方法适用于二元硅化物和锗化物。我们首先证实了反萤石 Mg2Si 和 Mg2Ge 的效果，其中通过实验确定了通过与 Mg2Sn 合金化来提高功率因数。在高通量形式主义中，我们确定了六个以前未报告的双星，它们的传输特性随着体积的变化而有所改善。其中，六方晶系MoSi2、斜方晶系Ca2Si和Ca2Ge的zT随体积的增量最大。然后，我们对特殊的准随机结构进行超晶胞计算，以研究获得热力学稳定合金系统的可能性，该系统会产生必要的体积变化。我们发现，对于 Ca2Si 和 Ca2Ge，即使在低温下也很容易形成具有同构 Ca2Sn 的固溶体。
We explore a material design strategy to optimize the thermoelectric power factor. The approach is based on screening the band structure changes upon a controlled volume change. The methodology is applied to the binary silicides and germanides. We first confirm the effect in antifluorite Mg2Si and Mg2Ge where an increased power factor by alloying with Mg2Sn is experimentally established. Within a high-throughput formalism we identify six previously unreported binaries that exhibit an improvement in their transport properties with volume. Among these, hexagonal MoSi2 and orthorhombic Ca2Si and Ca2Ge have the highest increment in zT with volume. We then perform supercell calculations on special quasirandom structures to investigate the possibility of obtaining thermodynamically stable alloy systems which would produce the necessary volume changes. We find that for Ca2Si and Ca2Ge the solid solutions with the isostructural Ca2Sn readily forms even at low temperatures.