Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA and ENN Intelligent Energy Group, ENN Science Park, Langfang 065001, China.
ENN Intelligent Energy Group, ENN Science Park, Langfang 065001, China.
Phys Rev Lett. 2014 Jun 6;112(22):226801. doi: 10.1103/PhysRevLett.112.226801. Epub 2014 Jun 2.
Improving the thermoelectric figure of merit zT is one of the greatest challenges in material science. The recent discovery of topological insulators (TIs) offers new promise in this prospect. In this work, we demonstrate theoretically that zT is strongly size dependent in TIs, and the size parameter can be tuned to enhance zT to be significantly greater than 1. Furthermore, we show that the lifetime of the edge states in TIs is strongly energy dependent, leading to large and anomalous Seebeck effects with an opposite sign to the Hall effect. These striking properties make TIs a promising material for thermoelectric science and technology.
提高热电器件的品质因数 zT 是材料科学领域面临的最大挑战之一。最近拓扑绝缘体（TI）的发现为此提供了新的希望。在这项工作中，我们从理论上证明了 zT 在 TI 中强烈依赖于尺寸，并且可以通过调整尺寸参数来提高 zT，使其显著大于 1。此外，我们还表明 TI 中边缘态的寿命强烈依赖于能量，导致出现大的反常塞贝克效应，其符号与霍尔效应相反。这些显著的特性使得 TI 成为热电科学和技术中很有前途的材料。
