Peierls distortion as a route to high thermoelectric performance in In4Se3-δ crystals
Peierls distortion as a route to high thermoelectric performance in In4Se3-δ crystals
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DOI：
10.1038/nature08088
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发表时间：
2009-06-18
期刊：
影响因子：
64.8
通讯作者：
Kotliar, Gabriel
中科院分区：
文献类型：
--
作者：
Rhyee, Jong-Soo;Lee, Kyu Hyoung;Kotliar, Gabriel
热电能量收集（将废热转化为有用的电能）对于能源可持续性具有重要意义。主要障碍是将热能转化为电能的材料的热电效率较低，通过热电品质因数 ZT 进行量化。用于中温 (500-900K) 热电发电机的最佳可用 n 型材料具有 1 或更低的相对较低的 ZT，因此人们对寻找提高此品质因数的途径非常感兴趣 (1)。在这里，我们报告了一种二元晶体 n 型材料 In4Se3-delta，它在 705K 温度下达到了 1.48 的 ZT 值，对于块体材料来说非常高。使用高分辨率透射电子显微镜、电子衍射和第一原理计算，我们证明了这种材料支持电荷密度波不稳定性，这是导致在电和热传输中观察到的大各向异性的原因。高ZT值是高塞贝克系数和电荷密度波平面内低热导率的结果。我们的结果提出了寻找高性能热电材料的新方向，利用电荷密度波引起的固有纳米结构体特性。
Thermoelectric energy harvesting-the transformation of waste heat into useful electricity-is of great interest for energy sustainability. The main obstacle is the low thermoelectric efficiency of materials for converting heat to electricity, quantified by the thermoelectric figure of merit, ZT. The best available n-type materials for use in mid-temperature (500-900K) thermoelectric generators have a relatively low ZT of 1 or less, and so there is much interest in finding avenues for increasing this figure of merit(1). Here we report a binary crystalline n-type material, In4Se3-delta, which achieves the ZT value of 1.48 at 705K-very high for a bulk material. Using high-resolution transmission electron microscopy, electron diffraction, and first-principles calculations, we demonstrate that this material supports a charge density wave instability which is responsible for the large anisotropy observed in the electric and thermal transport. The high ZT value is the result of the high Seebeck coefficient and the low thermal conductivity in the plane of the charge density wave. Our results suggest a new direction in the search for high-performance thermoelectric materials, exploiting intrinsic nanostructural bulk properties induced by charge density waves.