The chiral anomaly is one of the unusual effects of Weyl fermions and has attracted much interest. Experimental observation of this effect has largely been focused on a negative longitudinal magnetoresistance, which, however, has been proven to be insufficient. Thermoelectric experiment, a technique complimentary to the electrical resistivity and able to the capability to reveal the energy dependence of electron transport, has not been reported in many relevant semimetals. Here, we study the electrical and thermoelectric properties of a topological semimetal, $\mathrm{Zr}{\mathrm{Te}}_5$. Besides a previously reported negative magnetoresistance (NMR), a negative magnetothermopower (MTEP) is observed when the magnetic field is parallel to the temperature gradient. Both the magnetoconductivity and MTEP follow a quadratic dependence on the magnetic field. Moreover, the quadratic coefficient of MTEP is about twice as large as that of magnetoconductivity. These observations are consistent with the effect of the chiral anomaly. We also discuss other possible origins of these observations, such as current jetting, ionized impurity scattering, and spin-related effects.

中文翻译：

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拓扑半金属ZrTe5中的负纵向磁热能

手性异常是韦尔费米子的不寻常影响之一，引起了人们的极大兴趣。对这种效应的实验观察主要集中在负的纵向磁阻上，但是事实证明这是不够的。在许多相关的半金属中，尚未报道过热电实验，它是一种与电阻率互补的技术，能够揭示电子传输的能量依赖性。在这里，我们研究拓扑半金属的电和热电特性，$锆{特}_5$。除了先前报道的负磁阻（NMR），当磁场平行于温度梯度时，还会观察到负磁热能（MTEP）。磁导率和MTEP都依赖于磁场的二次方。而且，MTEP的二次系数约为磁导率的两倍。这些观察结果与手性异常的影响是一致的。我们还将讨论这些观察结果的其他可能来源，例如电流喷射，电离杂质散射和自旋相关效应。