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

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.Comment: 14 pages, 5 figure

Research on Evaluation of the MANET System Survivability

AbstractThrough the limitations of current evaluation about the MANET system survivability, a quantitative evaluation method based on grey relation analysis is proposed. First, the typical grey relation analysis method has been improved and the quantitative evaluation model base on the network entropy difference was established. Then the change of every key service's survivability situation is assessed by using the network entropy difference. At last the MANET system is simulated to test method of grey relation analysis, and the calculating result indicates that the proposed method can effectively evaluate the actual survivability of the MANET system