标题： 通过能带结构和填充控制提高狄拉克半金属 Cd$_{3}$As$_{2}$的热电优值 显示英文标题

标题： Enhancement of the Thermoelectric Figure of Merit in the Dirac Semimetal Cd$_{3}$As$_{2}$ by Band-Structure and -Filling Control

摘要： 拓扑材料由于其特有的能带结构，在量子物理中引发了各种新现象，因此引起了相当多的研究兴趣。 从功能材料的角度来看，它们也具有吸引力：拓扑材料具有增强的热电效率潜力，因为它们具备所需的要素，如中等载流子浓度、高迁移率、重元素等。 在此背景下，本工作报道了在将平凡半导体Zn$_{3}$As$_{2}$合金化后，拓扑狄拉克半金属Cd$_{3}$As$_{2}$的热电性能得到了增强。 这使得能够在Cd$_{3-x}$Zn$_{x}$As$_{2}$中对带填充和带拓扑结构进行精细调控。 因此，在高温下，热电优值在$x = 0.6$和$x = 1.2$附近超过 0.5。 前者是由于功率因数的增强，而后者是由于热导率的强烈抑制。 此外，从第一性原理能带结构计算的角度来看，该系统中的赛贝克系数被理论评估，这表明当穿过$x = 1.2$时，能带结构的拓扑特性发生变化。 显示英文摘要

摘要： Topological materials attract a considerable research interest because of their characteristic band structure giving rise to various new phenomena in quantum physics. Beside this, they are tempting from a functional materials point of view: Topological materials bear potential for an enhanced thermoelectric efficiency because they possess the required ingredients, such as intermediate carrier concentrations, large mobilities, heavy elements etc. Against this background, this work reports an enhanced thermoelectric performance of the topological Dirac semimetal Cd$_{3}$As$_{2}$ upon alloying the trivial semiconductor Zn$_{3}$As$_{2}$. This allows to gain fine-tuned control over both the band filling and the band topology in Cd$_{3-x}$Zn$_{x}$As$_{2}$. As a result, the thermoelectric figure of merit exceeds 0.5 around $x = 0.6$ and $x = 1.2$ at elevated temperatures. The former is due to an enhancement of the power factor, while the latter is a consequence of a strong suppression of the thermal conductivity. In addition, in terms of first-principle band structure calculations, the thermopower in this system is theoretically evaluated, which suggests that the topological aspects of the band structure change when traversing $x = 1.2$.