Graduate School of Information Science and Technology, Hokkaido University, N14W9, Kita, Sapporo, 060-0814, Japan.
Institute of Engineering Innovation, The University of Tokyo, 2-11-16 Yayoi, Bunkyo, Tokyo, 113-8656, Japan.
Nat Commun. 2018 Jun 20;9(1):2224. doi: 10.1038/s41467-018-04660-4.
Two-dimensional electron systems have attracted attention as thermoelectric materials, which can directly convert waste heat into electricity. It has been theoretically predicted that thermoelectric power factor can be largely enhanced when the two-dimensional electron layer is far narrower than the de Broglie wavelength. Although many studies have been made, the effectiveness has not been experimentally clarified thus far. Here we experimentally clarify that an enhanced two-dimensionality is efficient to enhance thermoelectric power factor. We fabricated superlattices of [N unit cell SrTiNb O|11 unit cell SrTiO]-there are two different de Broglie wavelength in the SrTiNb O system. The maximum power factor of the superlattice composed of the longer de Broglie wavelength SrTiNb O exceeded ∼5 mW m K, which doubles the value of optimized bulk SrTiNb O. The present approach-use of longer de Broglie wavelength-is epoch-making and is fruitful to design good thermoelectric materials showing high power factor.
二维电子系统作为热电材料引起了人们的关注，因为它们可以将废热直接转化为电能。理论上预测，当二维电子层远小于德布罗意波长时，热电功率因子可以大大增强。尽管已经进行了许多研究，但迄今为止，其有效性尚未在实验中得到证实。在这里，我们通过实验证实了增强二维性对于增强热电功率因子是有效的。我们制备了[N 个单胞 SrTiNbO|11 个单胞 SrTiO]的超晶格-在 SrTiNbO 体系中有两个不同的德布罗意波长。由较长德布罗意波长 SrTiNbO 组成的超晶格的最大功率因子超过了约 5 mW m K，是优化的块状 SrTiNbO 的两倍。本方法-使用较长的德布罗意波长-是开创性的，并且对于设计表现出高功率因子的良好热电材料是富有成效的。
