Quantum transport in three-dimensional Weyl electron system -- in the presence of charged impurity scattering

Quantum transport in 3D Wey electron system with the charged impurity is studied theoretically using a self-consistent Born approximation (SCBA). The scattering strength is characterized by the effective fine structure constant which depends on the dielectric constant and the Fermi velocity of the linear band. The Boltzmann transport theory works well in a condition that the level broadening is much smaller that the Fermi energy, but it fails near the Weyl point. At the Weyl point, the conductivity takes a nearly constant value which is almost independent of the effective fine structure constant, even though the density of states linearly increases with the effective fine structure constant. The qualitative behavior is significantly different from the case of the Gaussian impurities, where the conductivity exhibits critical behavior and vanishes at the Weyl point below a certain critical disorder strength.