Role of Weyl cone tilting in the spin Hall effect of light

Abstract

We systematically study the role of Weyl cone tilting in the spin Hall effect of light (SHEL) in doped Weyl semimetals (WSMs), and propose a new scheme to determine the type of a WSM and to sense the tilt degree of Weyl cones precisely. It is found that in the case of a small amount of doping, the SHEL in type-I WSMs shows almost no dependence on the tilt degree of Weyl cones, while the SHEL in type-II WSMs is extremely sensitive to variations in the degree of tilt. However, in the case of a large amount of doping, not only the SHEL in type-II WSMs but also the SHEL in type-I WSMs show strong dependences on the tilt degree. These trends are mainly attributed to the variation of the real part of the Hall conductivity with the tilt degree. Remarkably, by using a quantum weak measurement, the tiny SHEL shifts can be amplified and detected to a desirable accuracy. Based on the obviously different tilt-dependent characteristics of amplified SHEL shifts in WSMs, we propose a new scheme to determine the type of a WSM and to sense the tilt degree precisely. By adjusting the doping level, the sensing sensitivity can reach up to 1461.55 µm per degree of tilt. This study may provide an application reference for the fabrication of WSM parameter sensors and other topological photoelectric devices.

Interference effect on Goos–Hänchen shifts of anisotropic medium interface

“…The discovery of the type II WSM not only establishes the link between particle physics and condensed matter but also may lead to new applications in the field of optoelectronics [49,50]. To find more novel anomalous effects in spin photonics, the combination between the Type II WSM and beam displacement has become the focus of attention in recent years [51][52][53][54][55][56][57]. In this section, we take the Type II WSM film as an example and focus on analyzing the influence of abnormal interference between the reflected light field and the cross-reflected light field on GH displacement for the anisotropic medium interface.…”

Goos–Hänchen and Imbert–Fedorov shifts in tiltedWeyl semimetals

“…Previous studies have shown that the optical conductivities play an important role in influencing the reflection coefficients, and may then affect the optical effects at the material surface. [31][32][33][34] For the purpose of establishing the models of GH and IF shifts in tilted WSMs more comprehensively, it is necessary to solve the reflection coefficients of WSMs and investigate the relationship between these coefficients and WSMs conductivities.…”

“…[33] We discussed the role of Weyl cone tilting in photonic spin Hall effect in tilted WSMs, and proposed a new method for determining the type of WSMs and sensing the tilt degree of Weyl cone precisely. [34] In spite of this, the beam shifts are rarely discussed in the case of tilted Weyl nodes, while the study plays an important role for the more comprehensive grasp of the light-WSMs interaction and the related application.…”

Enhanced and tunable transmitted group delays based on epsilon-near-zero response of Weyl semimetal

“…WSM has a graphene analogous Dirac-like linear dispersion that generates numerous excellent optical performances, such as controlled plasmon resonance 15 and distinctive optical nonlinearity 16 . Notably, WSM exhibits a three-dimensional Hamiltonian different from the two-dimensional graphene, which reveals numerous unique physical features, such as a remarkable quantum Hall effect 17 – 20 and chiral anomalies 21 . Furthermore, the Weyl nodes of WSM play a sink or source of the Berry curvature, serving as the equivalent magnetic field in momentum space, 22 so the optical responses of WSMs should be represented with axion electrodynamics 23 .…”

“…Meanwhile, because of the equivalent magnetic field, the dielectric constant tensor has nonzero off-diagonal components, thus resulting in cross-polarized transmission and reflection coefficients 24 . Recently, a wide range of optical phenomena in WSM-based systems, such as adjustable Goos-Hänchen shift, 25 large Kerr and Faraday effects, 24 , 26 and anomalous Hall effects, 17 – 20 has been discussed. Nevertheless, to our knowledge, there exist few reports on the group delays of the transmitted light in WSM-based systems and the feasible enhancement phenomena.…”