Conductivity of a Weyl semimetal with donor and acceptor impurities

TL;DR

This paper analyzes how impurities affect electrical conductivity in Weyl semimetals, revealing temperature and impurity concentration-dependent regimes with potential for experimental observation.

Contribution

It provides a detailed theoretical calculation of conductivity in impurity-doped Weyl semimetals, highlighting crossover behaviors and conditions for different transport regimes.

Findings

Conductivity scales as T^2 in certain regimes

Transport behavior varies with impurity compensation and temperature

Low-temperature transport can be effectively metallic

Abstract

We study transport in a Weyl semimetal with donor and acceptor impurities. At sufficiently high temperatures transport is dominated by electron-electron interactions, while the low-temperature resistivity comes from the scattering of quasiparticles on screened impurities. Using the diagrammatic technique, we calculate the conductivity $\sigma(T,\omega,n_A,n_D)$ in the impurities-dominated regime as a function of temperature $T$, frequency $\omega$, and the concentrations $n_A$ and $n_D$ of donors and acceptors and discuss the crossover behaviour between the regimes of low and high temperatures and impurity concentrations. In a sufficiently compensated material [$|n_A-n_D|\ll(n_A+n_D)$] with a small effective fine structure constant $\alpha$, $\sigma(\omega,T)\propto T^2/(T^{-2}-i\omega\cdot\text{const})$ in a wide interval of temperatures. For very low temperatures or in the case of an uncompensated material the transport is effectively metallic. We discuss experimental conditions necessary for realising each regime.