Giant thermoelectric Seebeck coefficient of two-dimensional electron gas in SrTiO3
Giant thermoelectric Seebeck coefficient of two-dimensional electron gas in SrTiO3
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DOI：
10.1038/nmat1821
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发表时间：
2007-02-01
期刊：
影响因子：
41.2
通讯作者：
Koumoto, Kunihito
中科院分区：
文献类型：
--
作者：
Ohta, Hiromichi;Kim, Sungwng;Koumoto, Kunihito
在不降低电导率（σ）的情况下提高塞贝克系数（S）对于实现表现出无量纲品质因数（ZT = S-2（.）s（.）T（.）kappa（-1））超过2，其中T是绝对温度，是热导率。在这里，我们证明了一个高密度的二维电子气（2DEG）限制在SrTiO 3中的单元电池层厚度产生异常大的垂直酒吧S垂直酒吧，大约五倍大于SrTiO 3块，同时保持高西格玛（2DEG）。在最好的情况下，我们观察到垂直条S垂直条= 850 mu VK-1和σ（2DEG）= 1.4 x 10（3）S cm（-1）。此外，通过使用室温下块状单晶SrTiO 3的kappa，我们估计2DEG的ZT类似于2.4，对应于具有2DEG作为有源区的完整器件的ZT类似于0.24。本方法使用2DEG提供了一种新的途径，实现实用的热电材料，而不使用有毒的重元素。
Enhancement of the Seebeck coeffcient (S) without reducing the electrical conductivity (sigma) is essential to realize practical thermoelectric materials exhibiting a dimensionless figure of merit (ZT = S-2 (.) s (.) T (.) kappa(-1)) exceeding 2, where T is the absolute temperature and. is the thermal conductivity. Here, we demonstrate that a high-density two-dimensional electron gas (2DEG) confined within a unit cell layer thickness in SrTiO3 yields unusually large vertical bar S vertical bar, approximately five times larger than that of SrTiO3 bulks, while maintaining a high sigma(2DEG). In the best case, we observe vertical bar S vertical bar = 850 mu VK-1 and sigma(2DEG) = 1.4 x 10(3) S cm(-1). In addition, by using the kappa of bulk single-crystal SrTiO3 at room temperature, we estimate ZT similar to 2.4 for the 2DEG, corresponding to ZT similar to 0.24 for a complete device having the 2DEG as the active region. The present approach using a 2DEG provides a new route to realize practical thermoelectric materials without the use of toxic heavy elements.