Remarkable thermoelectric performance in BaPdS2 via pudding-mold band structure, band convergence, and ultralow lattice thermal conductivity
Remarkable thermoelectric performance in BaPdS2 via pudding-mold band structure, band convergence, and ultralow lattice thermal conductivity
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DOI：
10.1103/physrevmaterials.3.015403
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发表时间：
2018-10
影响因子：
3.4
通讯作者：
Eric B. Isaacs;C. Wolverton
中科院分区：
文献类型：
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作者：
Eric B. Isaacs;C. Wolverton
高效的热电材料需要材料特性的罕见和禁忌的组合：大电导率，大塞贝克系数和低热导率。实现前两个特性的一种策略是通过在晶体动量空间的不同区域中包含平坦和色散部分的低能电子带，称为布丁模带结构。在这里，我们说明，BaPdS$_2$成功地实现了布丁模具带结构，有助于一个大的热电功率因数，由于其各向异性的晶体结构包含锯齿形链的边缘共享正方形平面PdS$_4$单元。此外，BaPdS 2 $由于其横向声学声子分支中的极软和非谐相互作用，表现出超低的晶格热导率，从而也实现了第三种性质。我们预测一个非常大的热电品质因数，峰值在2和3之间的两个三个结晶方向，这表明BaPdS$_2$值得实验研究。
Efficient thermoelectric materials require a rare and contraindicated combination of materials properties: large electrical conductivity, large Seebeck coefficient, and low thermal conductivity. One strategy to achieve the first two properties is via low-energy electronic bands containing both flat and dispersive parts in different regions of crystal momentum space, known as a pudding-mold band structure. Here, we illustrate that BaPdS$_2$ successfully achieves the pudding-mold band structure, contributing to a large thermoelectric power factor, due to its anisotropic crystal structure containing zig-zag chains of edge-sharing square planar PdS$_4$ units. In addition, BaPdS$_2$ exhibits ultralow lattice thermal conductivity, and thus also achieves the third property, due to extremely soft and anharmonic interactions in its transverse acoustic phonon branch. We predict a remarkably large thermoelectric figure of merit, with peak values between 2 and 3 for two of the three crystallographic directions, suggesting BaPdS$_2$ warrants experimental investigation.