Beneficial Contribution of Alloy Disorder to Electron and Phonon Transport in Half‐Heusler Thermoelectric Materials
Beneficial Contribution of Alloy Disorder to Electron and Phonon Transport in Half‐Heusler Thermoelectric Materials
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DOI：
10.1002/adfm.201300663
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发表时间：
2013-11
影响因子：
19
通讯作者：
Hanhui Xie;Heng Wang;Y. Pei;C. Fu;Xiao-hua Liu;G. J. Snyder;Xinbing Zhao;T. Zhu
中科院分区：
文献类型：
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作者：
Hanhui Xie;Heng Wang;Y. Pei;C. Fu;Xiao-hua Liu;G. J. Snyder;Xinbing Zhao;T. Zhu
电子和声子输运特性决定了热电材料用于发电或制冷的潜力。这项工作表明，不同于大多数具有主要声学声子散射的高性能热电材料，有前途的ZrNiSn基半Heusler热电固溶体表现出合金散射主导的电荷输运。低变形势和低合金散射势被发现的固溶体，这是有益的，以保持相对较高的电子迁移率，尽管大的有效质量，可以是内在的有利功能，有助于显着高功率因数的ZrNiSn基合金。对不同声子散射机制的定量描述表明，点缺陷散射是决定固溶体声子输运过程的最重要机制。目前的研究结果表明，合金化可以是一种有效的方法，这种材料系统，以提高热电优值ZT通过降低声子热导率，同时尽量减少由于低合金散射电位的电荷迁移率的恶化。
Electron and phonon transport characteristics determines the potential of thermoelectric materials for power generation or refrigeration. This work shows that, different from most of high performance thermoelectric materials with dominant acoustic phonon scattering, the promising ZrNiSn based half‐Heusler thermoelectric solid solutions exhibit an alloy scattering dominated charge transport. A low deformation potential and a low alloy scattering potential are found for the solid solutions, which is beneficial to maintain a relatively high electron mobility despite of the large effective mass, and can be intrinsic favorable features contributing to the noticeably high power factors of ZrNiSn based alloys. A quantitive description of the different phonon scattering mechanisms suggests that the point defect scattering is the most important mechanism that determines the phonon transport process of the solid solutions. The present results indicate that alloying can be an effective approach for such materials systems to enhance thermoelectric figure of merit ZT by reducing phonon thermal conductivity, while minimizing the deterioration of charge mobility due to the low alloy scatteirng potential.