Current-voltage characteristics of Weyl semimetal semiconducting devices, Veselago lenses, and hyperbolic Dirac phase

The current-voltage characteristics of a new range of devices built around Weyl semimetals has been predicted using the Landauer formalism. The potential step and barrier have been reconsidered for a three-dimensional Weyl semimetals, with analogies to the two-dimensional material graphene and to optics. With the use of our results we also show how Veselago lens can be made from Weyl semimetals, e.g. from NbAs and NbP. Such lens may have many practical applications and can be used as a probing tip in a scanning tunneling microscope (STM). Because of the ballistic character of Weyl fermion transport inside the semimetal tip and ideal focusing of the Weyl fermions by Veselago lens on the surface of the tip one may create a very narrow electron beam from the tip to the surface of the studied material. With such Weyl semimetal probing tip the resolution of the present STMs can be improved significantly, and one may image not only individual atoms but also individual electron orbitals and chemical bonding and therewith to resolve the long-term issue of the chemical and hydrogen bonds formation. We show that applying a pressure to the Weyl semimental having no centre of spacial inversion one may model a matter at extreme conditions such as that arising in vicinity of a Black Hole. As the materials Cd3As2 and Na3Bi show an asymmetry in their Dirac cones, a scaling factor was used to model this asymmetry. The scaling factor created additional regions of no propagation and condensed the appearance of resonances. We argue that under external pressure there in Weyl semimetals may arise a topological phase transition, where the electron transport changes character and becomes anisotropic. There a hyperbolic Dirac phases occurs where there is a strong light absorption and photo-current generation.