Chiral-anomaly-induced angular narrowing of the positive longitudinal magnetoconductivity in Weyl semimetals

Abstract

By generalizing the Landau quantization Boltzmann equation to a finite-size system, we investigate the magnetotransport in disordered Weyl semimetals (WSMs) for both the ballistic and diffusive regimes. It is found that, in the diffusive limit, the chiral chemical potential would drive extra electrical current to flow through the chiral channels in the n=0 Landau levels, leading to emergence of the positive longitudinal magnetoconductivity (LMC). The positive LMC will exhibit the angular narrowing phenomenon if ℏω_{c}≫E_{F}sqrt[l_{a}/l_{e}], where ω_{c}, E_{F}, and l_{a(e)} denote, respectively, the cyclotron frequency, the Fermi energy, and the intravalley (intervalley) relaxation length. The anomalous magnetic field dependence of the angular narrowing, i.e., the width and height of the positive LMC peak could increase or decrease with increasing the magnetic field, can be attributable to quantum oscillations of the chiral anomaly. In addition, the quantum oscillations are sensitive to the temperature and impurity scattering, which may also cause some other anomalous properties for the LMC. Our findings are helpful to understand the anomalous behaviors of the positive LMC in WSMs.