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

Abstract

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 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 a Veselago lens can be made from Weyl semimetals, e.g., from NbAs and NbP. Such a lens may have many practical applications and can be used as a probing tip in a scanning tunneling microscope (STM). The ballistic character of Weyl fermion transport inside the semimetal tip, combined with the ideal focusing of the Weyl fermions (by Veselago lens) on the surface of the tip may create a very narrow electron beam from the tip to the surface of the studied material. With a 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 or chemical bonding and therewith to resolve the long-term issue of chemical and hydrogen bond formation. We show that applying a pressure to the Weyl semimental, having no center of spatial inversion, one may model matter at extreme conditions, such as those arising in the vicinity of a black hole. As the materials Cd 3 As 2 and Na 3 Bi 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 an external pressure there may arise a topological phase transition in Weyl semimetals, where the electron transport changes character and becomes anisotropic. There a hyperbolic Dirac phase occurs where there is a strong light absorption and photocurrent generation.

Electronic non-coplanar refraction and deflected diffraction of Weyl-node-mismatch junctions

“…Since the Weyl semimetal is the 3D counterpart of graphene, the fantasy electron optical effects found in graphene are also expected in Weyl semimetals. The 3D version of Klein tunneling in Weyl materials was studied [19], the negative refraction and the Veselago focusing in Weyl semimetals were discussed [19][20][21][22], and the Imbert-Fedorov shift and Goos-Hänchen shift, for the reflection as well as the transmission in Weyl materials, were reported [23][24][25][26].…”

Ab initio optical and energy loss spectra of transition metal monopnictides TaAs, TaP, NbAs, and NbP

“…The presence of the Weyl nodes confers these materials with novel properties such as Fermi arcs of surface states 3,7 , anomalous and spin Hall conductivity [8][9][10][11][12] , negative magnetoresistance 13 , and the Adler-Bell-Jackiw chiral anomaly 14 . Interesting applications of TWSs as materials for Veselago lenses have been predicted 15 .…”

Vortex of beam shift induced by mono-chiral interface states

“…The novel electron optics effects ever found in graphene are expected in Weyl semimetals. The 3D version of Klein tunneling, negative refraction and Veselago focusing were discussed in Weyl semimetals [26][27][28][29]. The electron beam shift on p-n junction interfaces has not only longitudinal but also transverse components, respectively called Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts, the latter of which does not exist in graphene [30][31][32], and the beam shift for transmission that was not noticed in solid media previously, was pointed out recently [30].…”