Weyl semimetals provide the realization of Weyl fermions in solid-state physics. Among all the physical phenomena that are enabled by Weyl semimetals, the chiral anomaly is the most unusual one. Here, we report signatures of the chiral anomaly in the magneto-transport measurements on the first Weyl semimetal TaAs. We show negative magnetoresistance under parallel electric and magnetic fields, that is, unlike most metals whose resistivity increases under an external magnetic field, we observe that our high mobility TaAs samples become more conductive as a magnetic field is applied along the direction of the current for certain ranges of the field strength. We present systematically detailed data and careful analyses, which allow us to exclude other possible origins of the observed negative magnetoresistance. Our transport data, corroborated by photoemission measurements, first-principles calculations and theoretical analyses, collectively demonstrate signatures of the Weyl fermion chiral anomaly in the magneto-transport of TaAs.
翻译:在固态物理学中,Weyl 半金属可以实现Weyl fermics。在所有由Wyl 半金属促成的物理现象中,手动异常现象是最不寻常的现象。这里,我们报告在第一个Weyl 半金属塔阿的磁性运输测量中出现手性异常的特征。我们在平行的电磁场下显示负磁性,即与在外部磁场下抗力增加的大多数金属不同,我们观察到,我们的高流动性塔亚斯样本变得更加导电导性强,因为磁场正在沿着当前方向对地表强度的某些范围进行。我们提供了系统详细的数据和仔细的分析,使我们能够排除观察到的负磁性磁性的其他可能来源。我们的运输数据,通过光感应测量、第一原则计算和理论分析得到证实,共同展示了Taas磁性运输中的Wyl vermociral异常的特征。