Effects of surface potentials on Goos-Haenchen and Imbert-Fedorov shifts in Weyl semimetals

TL;DR

This paper investigates how surface potentials from impurities affect the Goos-Haenchen and Imbert-Fedorov shifts in Weyl semimetals, revealing potential nullification of the IF shift and valley inversion, thus guiding future experimental and device applications.

Contribution

It provides a detailed analysis of impurity-induced surface potentials on GH and IF shifts in Weyl semimetals using a transfer matrix approach, highlighting their impact on observable phenomena.

Findings

Surface potentials can nullify the IF shift.

Impurities induce valley inversion effects.

Guides for experimental characterization of Weyl semimetals.

Abstract

Weyl semimetals exhibit exotic transport responses, among which, recently Goos-Haenchen (GH) and Imbert-Fedorov (IF) effects have received a revived attention, which are, otherwise, well-studied phenomena in optical systems and certain electronic systems. Besides the usual parametric dependence of the shifts inherited from the underlying Hamiltonian to describe the Weyl system and/or that induced by external controls, the IF shift further carries a topological identity -- it depends on the chirality of the Weyl cones. A realistic system of Weyl semimetal naturally accommodates surface potentials induced by impurities present on its surface that could pose impediments to observe clean transport signatures predicted in theoretical models. Classifying these potentials, we study their effects on GH and IF shifts to provide useful guidance to future experiments that are tuned to the objective of characterizing Weyl semimetals and for a possible realisation of novel devices based on these phenomena. A transfer matrix-based approach is invoked to study the profile of Weyl wavefunctions across the interface which is hosting the impurity potentials, revealing that such potentials can lead to several discerning effects which, in certain cases, extend even to nullifying the IF shift completely and giving rise to phenomenon like valley inversion.