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

TL;DR

This paper investigates quantum transport in 3D Weyl electron systems with charged impurity scattering, revealing a nearly constant conductivity at the band touching point independent of impurity strength, contrasting with Gaussian impurity cases.

Contribution

It provides a theoretical analysis using SCBA showing the failure of Boltzmann theory and the unique conductivity behavior at the Weyl point due to charged impurities.

Findings

Conductivity remains nearly constant at the Weyl point regardless of impurity strength.

Boltzmann theory fails at the band touching point for charged impurities.

Distinct behavior compared to Gaussian impurities where minimum conductivity vanishes.

Abstract

We theoretically study the quantum transport in three-dimensional Weyl electron system in the presence of the charged impurity scattering using a self-consistent Born approximation (SCBA). The scattering strength is characterized by the effective fine structure constant $\alpha$, which depends on the dielectric constant and the Fermi velocity of the linear band. We find that the Boltzmann theory fails at the band touching point, where the conductivity takes a nearly constant value almost independent of $\alpha$, even though the density of states linearly increases with $\alpha$. There the magnitude of the conductivity only depends on the impurity density. The qualitative behavior is quite different from the case of the Gaussian impurities, where the minimum conductivity vanishes below a certain critical impurity strength.