Magnetic field effect on linear and nonlinear conductivity in a quasi-one-dimensional Weyl semimetal with a charge density wave (TaSe₄)₂I is studied. Longitudinal magnetoresistance in all known regimes of charge-density wave motion (linear conduction, creep, sliding, “Fröhlich superconductivity”) is positive and does not exceed a fraction of per cent. Similar magnetotransport measurements were performed in samples profiled by focused ion beams is such a way that motion of the charge-density wave in them is accompanied by phase slip of the charge-density wave. In such samples, a peak-like non-parabolic negative magnetoresistance is observed in relatively small magnetic fields B ≲ 4 T in the nonlinear conduction regime in both longitudinal and transverse geometries. Our results differ significantly from ones obtained earlier and raise the question concerning conditions for observing the axion anomaly in Weyl semimetals in the Peierls state.

研究了在电荷密度波为（TaSe ₄）₂ I的准一维Weyl半金属中磁场对线性和非线性电导率的影响。在所有已知的电荷密度波运动方式（线性传导，蠕变，滑动，“Fröhlich超导性”）中，纵向磁阻为正，且不超过百分之一。在聚焦离子束轮廓分析的样品中进行了类似的磁传输测量，使得样品中的电荷密度波运动伴随着电荷密度波的相移。在这种样品中，在相对较小的磁场B中观察到峰状的非抛物线形负磁阻T 4 T在纵向和横向几何形状的非线性传导方式中。我们的结果与先前获得的结果有显着差异，并提出了有关在Peierls状态下观测Weyl半金属轴突异常的条件的问题。