Competition between the inter-valley scattering and the intra-valley scattering on magnetoconductivity induced by screened Coulomb disorder in Weyl semimetals

TL;DR

This paper investigates how screened Coulomb disorder affects magnetoconductivity in Weyl semimetals, revealing the competition between inter-valley and intra-valley scattering and their impact on experimental observations.

Contribution

It introduces a detailed analysis of the interplay between inter-valley and intra-valley scattering in Weyl semimetals with screened Coulomb impurities, extending beyond one-node models.

Findings

Positive longitudinal magnetoconductivity under parallel fields matches experimental negative LMR.

Magnetoconductivity sensitivity to screening length affects the observability of negative LMR.

Inter-valley scattering can dominate over intra-valley scattering in strong magnetic fields and small screening lengths.

Abstract

Recent experiments on Weyl semimetals reveal that charged impurities may play an important role. We use a screened Coulomb disorder to model the charged impurities, and study the magneto-transport in a two-node Weyl semimetal. It is found that when the external magnetic field is applied parallel to the electric field, the calculated longitudinal magnetoconductivity shows positive in the magnetic field, which is just the negative longitudinal magnetoresistivity (LMR) observed in experiments. When the two fields are perpendicular to each other, the transverse magnetoconductivities are measured. It is found that the longitudinal (transverse) magnetoconductivity is suppressed (enhanced) sensitively with increasing the screening length. This feature makes it hardly to observe the negative LMR in Weyl semimetals experimentally owing to a small screening length. Our findings gain insight into further understanding on recently actively debated magneto-transport behaviors in Weyl semimetals. Furthermore we studied the relative weight of the inter-valley scattering and the intra-valley scattering. It shows that the former is as important as the latter and even dominates in the case of strong magnetic fields and small screening length. We emphasize that the discussions on inter-valley scattering is out of the realm of one-node model which has been studied.