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arXiv 1607.00618cond-mat.mtrl-sci
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Thermoelectric Effects和拓扑绝缘体

Thermoelectric Effects and Topological Insulators

Yong Xu

摘要:

拓扑绝缘体(TI)的发现为热电材料的发展提供了新的机遇,因为许多TI(如Bi $_2$ Te $_3$)是优良的热电材料。在这篇综述中,我们将首先描述一般的TE性质的TI,并表明,共存的体和边界状态的TI介绍了不寻常的TE性质,包括强尺寸效应和异常塞贝克效应。重要的是,TI的TE优值$zT$不再是固有性质,而是强烈依赖于几何尺寸。可以调整二维TI的几何参数以将$zT$增强为显著大于1。然后将讨论一些三维TI的原理验证实验,这些实验观察到与材料的拓扑性质密切相关的非常规TE现象。然而,目前的实验表明,金属表面状态,如果他们的高迁移率的优势没有得到充分利用,将是有害的TE性能。最后,我们对拓扑材料的未来工作进行了展望,这为发现奇异TE效应提供了很大的可能性,并可能导致在改进$zT$方面的重大突破。

英文摘要:

The recent discovery of topological insulator (TI) offers new opportunities for the development of thermoelectrics, because many TIs (like Bi$_2$Te$_3$) are excellent thermoelectric (TE) materials. In this review, we will first describe the general TE properties of TIs and show that the coexistence of the bulk and boundary states in TIs introduces unusual TE properties, including strong size effects and anomalous Seebeck effect. Importantly, the TE figure of merit $zT$ of TIs is no longer an intrinsic property, but depends strongly on the geometric size. The geometric parameters of two-dimensional TIs can be tuned to enhance $zT$ to be significantly greater than 1. Then a few proof-of-principle experiments on three-dimensional TIs will be discussed, which observed unconventional TE phenomena that are closely related to the topological nature of the materials. However, current experiments indicate that the metallic surface states, if their advantage of high mobility is not fully utilized, would be detrimental to TE performance. Finally we provide an outlook for future work on topological materials, which offers great possibilities to discover exotic TE effects and may lead to significant breakthroughs in improving $zT$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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