Giant thermoelectric power factor in ultrathin FeSe superconductor
Giant thermoelectric power factor in ultrathin FeSe superconductor
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DOI：
10.1038/s41467-019-08784-z
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发表时间：
2019-02-18
影响因子：
16.6
通讯作者：
Iwasa, Yoshihiro
中科院分区：
文献类型：
--
作者：
Shimizu, Sunao;Shiogai, Junichi;Iwasa, Yoshihiro
热电效应作为能量收集技术的概念正在重新引起人们的兴趣。由于低维电荷和声子传输，纳米材料被认为是实现高效热电转换的关键。在这方面，最近出现的二维材料可能是具有新颖热电功能的有前途的候选材料。在这里，我们报道了 FeSe 超薄膜，一种高 T-c 超导体（T-c；超导转变温度），表现出优异的热电响应。随着厚度d的减小，电导率增加，并出现高温超导；出乎意料的是，由于二维性质的出现，塞贝克系数 alpha 显示出伴随的增加。当d减小到接近1 nm时，50 K和室温下的热电功率因数分别达到前所未有的高达13,000和260 mu W cm(-1) K-2的值。高T-c超导体中的大热电效应表明二维层状材料在多功能化方面具有巨大潜力。
The thermoelectric effect is attracting a renewed interest as a concept for energy harvesting technologies. Nanomaterials have been considered a key to realize efficient thermoelectric conversions owing to the low dimensional charge and phonon transports. In this regard, recently emerging two-dimensional materials could be promising candidates with novel thermoelectric functionalities. Here we report that FeSe ultrathin films, a high-T-c superconductor (T-c; superconducting transition temperature), exhibit superior thermoelectric responses. With decreasing thickness d, the electrical conductivity increases accompanying the emergence of high-T-c superconductivity; unexpectedly, the Seebeck coefficient alpha shows a concomitant increase as a result of the appearance of two-dimensional natures. When d is reduced down to similar to 1 nm, the thermoelectric power factor at 50 K and room temperature reach unprecedented values as high as 13,000 and 260 mu W cm(-1) K-2, respectively. The large thermoelectric effect in high T-c superconductors indicates the high potential of two-dimensional layered materials towards multi-functionalization.