Weak antilocalization and localization in disordered and interacting Weyl semimetals

TL;DR

This paper derives formulas for conductivity and magnetoconductivity in disordered Weyl semimetals, highlighting weak antilocalization effects and their experimental signatures, while also exploring the crossover to localization under strong scattering.

Contribution

It provides a theoretical framework for understanding magnetotransport in Weyl semimetals, including the effects of disorder, interactions, and Berry curvature, with comparison to experimental data.

Findings

Magnetoconductivity is negative and proportional to the square root of magnetic field at low temperatures.

Weak antilocalization dominates near zero magnetic field, serving as a transport signature.

Strong intervalley scattering can induce a crossover from weak antilocalization to localization.

Abstract

Using the Feynman diagram techniques, we derive the finite-temperature conductivity and magnetoconductivity formulas from the quantum interference and electron-electron interaction, for a three-dimensional disordered Weyl semimetal. For a single valley of Weyl fermions, we find that the magnetoconductivity is negative and proportional to the square root of magnetic field at low temperatures, as a result of the weak antilocalization. By including the contributions from the weak antilocalization, Berry curvature correction, and Lorentz force, we compare the calculated magnetoconductivity with a recent experiment. The weak antilocalization always dominates the magnetoconductivity near zero field, thus gives one of the transport signatures for Weyl semimetals. In the presence of strong intervalley scattering and correlations, we expect a crossover from the weak antilocalization to weak localization. In addition, we find that the interplay of electron-electron interaction and disorder scattering always dominates the conductivity at low temperatures and leads to a tendency to localization. Finally, we present a systematic comparison of the transport properties of single-valley Weyl fermions, 2D massless Dirac fermions, and 3D conventional electrons.