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

The repertoire of G-protein-coupled receptors in Xenopus tropicalis

<p>Abstract</p> <p>Background</p> <p>The G-protein-coupled receptor (GPCR) superfamily represents the largest protein family in the human genome. These proteins have a variety of physiological functions that give them well recognized roles in clinical medicine. In <it>Xenopus tropicalis</it>, a widely used animal model for physiology research, the repertoire of GPCRs may help link the GPCR evolutionary history in vertebrates from teleost fish to mammals.</p> <p>Results</p> <p>We have identified 1452 GPCRs in the <it>X. tropicalis </it>genome. Phylogenetic analyses classified these receptors into the following seven families: <it>Glutamate</it>, <it>Rhodopsin</it>, <it>Adhesion</it>, <it>Frizzled</it>, <it>Secretin</it>, <it>Taste 2 </it>and <it>Vomeronasal 1</it>. Nearly 70% of <it>X. tropicalis </it>GPCRs are represented by the following three types of receptors thought to receive chemosensory information from the outside world: olfactory, vomeronasal 1 and vomeronasal 2 receptors.</p> <p>Conclusion</p> <p><it>X. tropicalis </it>shares a more similar repertoire of GPCRs with mammals than it does with fish. An examination of the three major groups of receptors related to olfactory/pheromone detection shows that in <it>X. tropicalis</it>, these groups have undergone lineage specific expansion. A comparison of GPCRs in <it>X. tropicalis</it>, teleost fish and mammals reveals the GPCR evolutionary history in vertebrates.</p