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

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 magnetotransport 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.

Transversal magnetotransport in Weyl semimetals: Exact numerical approach

“…The recent experiments triggered a renewed interest in the problem leading to the appearance of a number of theoretical studies reproducing and extending Abrikosov's earlier results. [27][28][29][30][31][32][33][34] Notably, the more realistic situation with a pair of nodes was accounted for in Refs. 27, 28, 30, and 33, while disorder was assumed to be of (uncorrelated) Gaussian white noise type in Refs.…”

Magneto-conductivity of Weyl semimetals: the roles of inter-valley scattering and high-order Feynman diagrams

“…And the high order bubble diagrams have the nontrivial effect on the longitudinal conductivity. To our knowledge, the influence of inter-valley scattering on the magnetoresistance of WSM begins to draw attention [46]. But the contribution of hight order terms must be treated carefully.…”

Magneto-transport properties of thin flakes of Weyl semiconductor tellurium*

“…Considering the relatively high carrier density of Te flakes arising from the large amounts of Te vacancies, the screened Coulomb potential may effectively affect the magnetotransport behaviors by introducing both the intra-valley scattering and intervalley scattering. [43] As the temperature decreases, the intervalley scattering takes a more important role in the transport behavior, as evidenced by the emergence of weak localization as well as the violation of Kohler's rule (see Note 3 and Fig. S6 in the supplementary material), leading to a transition from parabolic to linear field dependence of the longitudinal MC.…”

“…Note that in the theory developed by Son and Spivak, [40] there is an important assumption that the intra-valley scattering determines the transport performance while the intervalley scattering is negligible. [42] Ji et al [43,44] further explored the effects of both intra-valley and inter-valley scattering induced by the screened Coulomb potential, and revealed that the linear longitudinal MC is actually closely relevant to the enhanced contribution of the inter-valley scattering. Considering the relatively high carrier density of Te flakes arising from the large amounts of Te vacancies, the screened Coulomb potential may effectively affect the magnetotransport behaviors by introducing both the intra-valley scattering and intervalley scattering.…”