预测的II型Weyl半金属WTe $_2$的热电势和非常规能斯特
Thermopower and Unconventional Nernst in the Predicted Type-II Weyl Semi-metal WTe$_2$
摘要：
WTe $_2$是最近发现的一系列高迁移率半金属之一，其某些性质具有拓扑Dirac或Weyl金属的特征。它最有趣的特性之一是它在低温下表现出的不饱和巨磁阻。一个重要的问题是，在何种程度上这种属性可以归因于一个传统的半金属模型，其中一个高度补偿，高迁移率的金属表现出大的磁阻。在这里，我们表明，纵向热电势（塞贝克效应）的半金属WTe $_2$剥离薄片表现出周期性的符号变化约为零，随着磁场的增加，表明不同的电子和空穴朗道能级和几乎完全补偿的电子和空穴载流子密度。然而，与传统的半金属图片不一致，我们发现在低温下的能斯特效应的快速增强是非线性的磁场，这是符合外尔点附近的费米能量。因此，我们证明了WTe $_2$的外尔特征在其输运性质中所起的作用。
英文摘要：
WTe$_2$ is one of a series of recently discovered high mobility semimetals, some of whose properties are characteristic of topological Dirac or Weyl metals. One of its most interesting properties is the unsaturated giant magnetoresistance that it exhibits at low temperatures. An important question is the degree to which this property can be ascribed to a conventional semi-metallic model in which a highly compensated, high mobility metal exhibits large magnetoresistance. Here we show that the longitudinal thermopower (Seebeck effect) of semi-metallic WTe$_2$ exfoliated flakes exhibits periodic sign changes about zero with increasing magnetic field that indicates distinct electron and hole Landau levels and nearly fully compensated electron and hole carrier densities. However, inconsistent with a conventional semi-metallic picture, we find a rapid enhancement of the Nernst effect at low temperatures that is nonlinear in magnetic field, which is consistent with Weyl points in proximity to the Fermi energy. Hence, we demonstrate the role played by the Weyl character of WTe$_2$ in its transport properties.
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。
