Chiral anomaly in type-I Weyl semimetals: Comprehensive analysis within a semiclassical Fermi surface harmonics approach

Abstract

In Weyl semimetals, the chiral charge is not conserved in the presence of external nonorthogonal magnetic and electric fields; this chiral anomaly manifests itself in a negative longitudinal magnetoresistance. In this paper, we report on detailed calculations of transport properties of type-I Weyl semimetals with broken time-reversal and broken inversion symmetries, respectively, within a semiclassical Boltzmann approach. The use of Fermi surface harmonics provides a comprehensive and closed solution of the Boltzmann equation including the influence of the Lorentz force as well as $\mathbf{k}$-dependent scattering-out and scattering-in terms. Respecting a modified phase space volume, we identify additional contributions to the charge conductivity, which scale linearly with the magnetic field and can change the sign of the magnetoresistance in systems with broken inversion symmetry. Considering the scattering properties, the energy dependence of the chiral anomaly-related contribution to the charge conductivity is more pronounced than usually discussed. On top of this, we show for the Weyl semimetal TaAs that a misalignment of an applied magnetic field with the crystal axes can destroy the negative longitudinal magnetoresistance.