Transversal magnetoresistance and Shubnikov-de Haas oscillations in Weyl semimetals

TL;DR

This paper theoretically investigates the magnetoresistance and quantum oscillations in Weyl semimetals under magnetic fields, considering different disorder types and energy-shifted Weyl nodes, revealing large TMR and oscillations consistent with experiments.

Contribution

It provides a comprehensive theoretical analysis of TMR and Shubnikov-de Haas oscillations in Weyl semimetals with various disorder models and energy configurations, extending understanding of their magnetotransport properties.

Findings

Large TMR observed in Coulomb impurity models across broad magnetic field ranges.

Linear TMR in the ultra-quantum limit with only the zeroth Landau level.

Strong Shubnikov-de Haas oscillations in moderate magnetic fields.

Abstract

We explore theoretically the magnetoresistance of Weyl semimetals in transversal magnetic fields away from charge neutrality. The analysis within the self-consistent Born approximation is done for the two different models of disorder: (i) short-range impurties and (ii) charged (Coulomb) impurities. For these models of disorder, we calculate the conductivity away from charge neutrality point as well as the Hall conductivity, and analyze the transversal magnetoresistance (TMR) and Shubnikov-de Haas oscillations for both types of disorder. We further consider a model with Weyl nodes shifted in energy with respect to each other (as found in various materials) with the chemical potential corresponding to the total charge neutrality. In the experimentally most relevant case of Coulomb impurities, we find in this model a large TMR in a broad range of quantizing magnetic fields. More specifically, in the ultra-quantum limit, where only the zeroth Landau level is effective, the TMR is linear in magnetic field. In the regime of moderate (but still quantizing) magnetic fields, where the higher Landau levels are relevant, the rapidly growing TMR is supplemented by strong Shubnikov-de Haas oscillations, consistent with experimental observations.