State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, China.
International Center for Quantum Materials, Peking University, Beijing 100871, China.
Nat Commun. 2016 Oct 10;7:13013. doi: 10.1038/ncomms13013.
Discovery of Weyl semimetals has revived interest in Weyl fermions which has not been observed in high energy experiments. It now becomes possible to study, in solids, their exotic properties. Extensive photoemission spectroscopy and electrical resistivity experiments have been carried out. However, many other properties remain unexplored. Here we show the thermoelectric signature of the chiral anomaly of Weyl fermions in CdAs under a magnetic field. We observe a strong quadratic suppression of the thermopower when the magnetic field is parallel to the temperature gradient. The quadratic coefficient is nearly twice of that for the electrical conductivity. The thermopower reverses its sign in high fields. We show that all these intriguing observations can be understood in terms of the chiral anomaly of Weyl fermions. Our results reveal the anomalous thermoelectric property of Weyl fermions and provide insight into the chiral anomaly.
Weyl 半金属的发现重新激发了人们对高能实验中尚未观察到的 Weyl 费米子的兴趣。现在，有可能在固体中研究它们的奇异特性。已经进行了广泛的光电子能谱和电阻率实验。然而，还有许多其他性质尚待探索。在这里，我们在磁场下展示了 CdAs 中 Weyl 费米子手性反常的热电信号。当磁场与温度梯度平行时，我们观察到热功率的强烈二次抑制。二次系数几乎是电导率的两倍。在高磁场下，热功率会反转其符号。我们表明，所有这些有趣的观察结果都可以用 Weyl 费米子的手性反常来解释。我们的结果揭示了 Weyl 费米子异常的热电性质，并提供了对手性反常的深入了解。
