Single crystal growth and thermoelectric properties of Nowotny chimney-ladder compound Fe2Ge3
Single crystal growth and thermoelectric properties of Nowotny chimney-ladder compound Fe2Ge3
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DOI：
10.1103/physrevmaterials.7.125404
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发表时间：
2023-12
影响因子：
3.4
通讯作者：
Y. Xu;Yan Wu;Huibo Cao;S. Guo;Jiaqiang Yan;Xi Chen
中科院分区：
文献类型：
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作者：
Y. Xu;Yan Wu;Huibo Cao;S. Guo;Jiaqiang Yan;Xi Chen
具有无公度的Nowotny烟囱-阶梯（NCL）结构由于其低热导率而成为用于热电应用的有前景的材料。以前的实验研究主要集中在多晶样品上，导致对材料固有的热电性能及其低热导率的根本原因的理解有限。本文报道了单晶体的合成及其热电性能。用化学气相输运法生长的毫米级单晶可以用来研究本征热电性能。的Seebeck系数为负，其大小随温度线性增加，表现出简并型半导体行为。的电阻率和比热数据的分析表明，存在一个爱因斯坦模式的特征温度约为60 K，这表明存在低能量的光学声子。沿轴向的热导率在300 K时很低，并表现出几乎与温度无关的特性，这与以前的理论计算结果有很强的温度依赖性不同。低热导率可归因于低能量光学模式对声学声子的散射和非扩展扩散模式的存在，如另一种NCL化合物中所报道的。这项研究提供了有价值的见解的电气和热性能，这可以打开热电应用的未来发展的可能性。
with an incommensurate Nowotny chimney-ladder (NCL) structure is a promising material for thermoelectric applications due to its low thermal conductivity. Previous experimental studies onhave mainly focused on polycrystalline samples, resulting in a limited understanding of the material's intrinsic thermoelectric properties and the underlying causes of its low thermal conductivity. Here we report the synthesis and thermoelectric properties of single crystalline. Millimeter-sizedsingle crystals grown by the chemical vapor transport method enable the study of the intrinsic thermoelectric properties. The Seebeck coefficient ofis negative and its magnitude increases linearly with temperature, showing a degenerate-type semiconductor behavior. Analysis of the electrical resistivity and specific heat data indicates the existence of an Einstein mode with a characteristic temperature of about 60 K, suggesting the presence of low-energy optical phonons. The thermal conductivity ofalong theaxis is as low asat 300 K and exhibits a nearly temperature-independent characteristic, which is distinct from the previous theoretical calculations with a stronger temperature dependence. The low thermal conductivity may be attributed to the scattering of acoustic phonons by low-energy optical modes and the presence of non-extended diffuson modes, as reported in another NCL compound,. This study provides valuable insights into the electrical and thermal properties of, which can open up possibilities for future advances in thermoelectric applications.