Doping as a tuning mechanism for magnetothermoelectric effects to improve zT in polycrystalline NbP
Doping as a tuning mechanism for magnetothermoelectric effects to improve zT in polycrystalline NbP
复制标题
DOI：
10.1103/physrevb.107.115108
复制
发表时间：
2022-06
影响因子：
3.7
通讯作者：
E. F. Scott;Katherine A. Schlaak;Poulomi Chakraborty;C. Fu;S. Guin;Safa Khodabakhsh;A. Paz y Puente-A.-Paz-y
中科院分区：
文献类型：
--
作者：
E. F. Scott;Katherine A. Schlaak;Poulomi Chakraborty;C. Fu;S. Guin;Safa Khodabakhsh;A. Paz y Puente-A.-Paz-y
外尔半金属结合了拓扑效应和半金属效应，使其成为有趣且有效的热电传输特性的候选者。在这里，我们展示了多晶 NbP 的实验结果，证明了大能斯特效应和大磁塞贝克效应同时存在，这通常在相同温度下的单一材料中观察不到。我们将两个 NbP 多晶样品的输运结果与之前发表的工作进行了比较，观察了最大能斯特和磁-塞贝克热电势发生时的温度变化，同时仍然保持相似数量级的热电势。理论模型显示了掺杂如何通过改变与温度相关的化学势来强烈改变塞贝克和能斯特磁热电势，并且相应的计算为我们的结果提供了一致的解释。因此，我们提供掺杂作为一种调谐机制，用于将磁热电效应转移到适合器件应用的温度，从而在所需的工作温度下提高 zT。此外，同时存在大型能斯特热电和磁塞贝克热电的情况并不常见，如果附加使用热电，则可提供独特的设备优势。在这里，我们还提出了一种独特的热电装置，它将共同利用大型能斯特和磁塞贝克热电势来大大提高传统热电装置的输出和 zT。
Weyl semimetals combine topological and semimetallic effects, making them candidates for interesting and effective thermoelectric transport properties. Here, we present experimental results on polycrystalline NbP, demonstrating the simultaneous existence of a large Nernst effect and a large magneto-Seebeck effect, which is typically not observed in a single material at the same temperature. We compare transport results from two polycrystalline samples of NbP with previously published work, observing a shift in the temperature at which the maximum Nernst and magneto-Seebeck thermopowers occur, while still maintaining thermopowers of similar magnitude. Theoretical modeling shows how doping strongly alters both the Seebeck and Nernst magneto-thermopowers by shifting the temperature-dependent chemical potential, and the corresponding calculations provide a consistent interpretation of our results. Thus, we offer doping as a tuning mechanism for shifting magneto-thermoelectric effects to temperatures appropriate for device applications, improving zT at desirable operating temperature. Furthermore, the simultaneous presence of both a large Nernst and magneto-Seebeck thermopower is uncommon and offers unique device advantages if the thermopowers are used additively. Here, we also propose a unique thermoelectric device which would collectively harness the large Nernst and magneto-Seebeck thermopowers to greatly enhance the output and zT of conventional thermoelectric devices.