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

摘要

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