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Experimental validation of high thermoelectric performance in RECuZnP2 predicted by high-throughput DFT calculations
Materials Horizons ( IF 12.2 ) Pub Date : 2020-11-04 , DOI: 10.1039/d0mh01112f
Jan-Hendrik Pöhls 1 , Sevan Chanakian , Junsoo Park , Alex M Ganose , Alexander Dunn , Nick Friesen , Amit Bhattacharya , Brea Hogan , Sabah Bux , Anubhav Jain , Arthur Mar , Alexandra Zevalkink
Affiliation  

Accurate density functional theory calculations of the interrelated properties of thermoelectric materials entail high computational cost, especially as crystal structures increase in complexity and size. New methods involving ab initio scattering and transport (AMSET) and compressive sensing lattice dynamics are used to compute the transport properties of quaternary CaAl2Si2-type rare-earth phosphides RECuZnP2 (RE = Pr, Nd, Er), which were identified to be promising thermoelectrics from high-throughput screening of 20 000 disordered compounds. Experimental measurements of the transport properties agree well with the computed values. Compounds with stiff bulk moduli (>80 GPa) and high speeds of sound (>3500 m s−1) such as RECuZnP2 are typically dismissed as thermoelectric materials because they are expected to exhibit high lattice thermal conductivity. However, RECuZnP2 exhibits not only low electrical resistivity, but also low lattice thermal conductivity (∼1 W m−1 K−1). Contrary to prior assumptions, polar-optical phonon scattering was revealed by AMSET to be the primary mechanism limiting the electronic mobility of these compounds, raising questions about existing assumptions of scattering mechanisms in this class of thermoelectric materials. The resulting thermoelectric performance (zT of 0.5 for ErCuZnP2 at 800 K) is among the best observed in phosphides and can likely be improved with further optimization.

中文翻译:

通过高通量 DFT 计算预测的 RECuZnP2 高热电性能的实验验证

热电材料相关特性的准确密度泛函理论计算需要高计算成本,特别是随着晶体结构的复杂性和尺寸增加。涉及ab initio散射和传输 (AMSET) 和压缩传感晶格动力学的新方法用于计算四元 CaAl 2 Si 2型稀土磷化物 RECuZnP 2 (RE = Pr、Nd、Er)的传输特性通过高通量筛选 20 000 种无序化合物成为有前途的热电材料。传输特性的实验测量值与计算值非常吻合。具有刚性体积模量 (>80 GPa) 和高声速 (>3500 ms -1),例如RECuZnP 2通常被认为是热电材料,因为它们有望表现出高晶格热导率。然而,RECuZnP 2不仅表现出低电阻率,而且表现出低晶格热导率(~1 W m -1 K -1)。与先前的假设相反,AMSET 揭示极光声子散射是限制这些化合物电子迁移率的主要机制,这引发了对此类热电材料中现有散射机制假设的质疑。所得热电性能(对于 ErCuZnP 2 的zT为 0.5 在 800 K) 是磷化物中观察到的最好的之一,并且可以通过进一步优化得到改善。
更新日期:2020-11-27
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