Magnetoconductivity in Weyl semimetals: Effect of chemical potential and temperature

Abstract

We present detailed analyses of magnetoconductivities in a Weyl semimetal within the Born and self-consistent Born approximations. In the presence of charged impurities, linear magnetoresistance can occur when the charge carriers are mainly from the zeroth (n=0) Landau level. Interestingly, the linear magnetoresistance is very robust against changes of temperature as long as the charge carriers come mainly from the zeroth Landau level. We denote this parameter regime as the high-field regime. On the other hand, the linear magnetoresistance disappears once the charge carriers from the higher Landau levels can provide notable contributions. Our analysis indicates that the deviation from linear magnetoresistance is mainly due to the deviation of the longitudinal conductivity from 1/B behavior. We found two important features of the self-energy approximation: (i) A dramatic jump of σ[subscript xx], when the n=1 Landau level begins to contribute charge carriers, which is the beginning point of the middle-field regime, when decreasing the external magnetic field from high field; (ii) in the low-field regime, σ[subscript xx] exhibits B[superscript −5/3] behavior, causing the magnetoresistance ρ_{xx} to exhibit B[superscript 1/3] behavior. A detailed and careful numerical calculation indicates that the self-energy approximation (including both the Born and the self-consistent Born approximations) does not explain the recent experimental observation of linear magnetoresistance in Weyl semimetals.