Negative Refraction in Weyl Semimetals

Abstract

We theoretically propose that Weyl semimetals may exhibit negative refraction at some frequencies close to the plasmon frequency, allowing transverse magnetic (TM) electromagnetic waves with frequencies smaller than the plasmon frequency to propagate in the Weyl semimetals. The idea is justified by the calculation of reflection spectra, in which negative refractive index at such frequencies gives physically correct spectra. In this case, a TM electromagnetic wave incident to the surface of the Weyl semimetal will be bent with a negative angle of refraction. We argue that the negative refractive index at the specified frequencies of the electromagnetic wave is required to conserve the energy of the wave, in which the incident energy should propagate away from the point of incidence.

Optical Hall effect and gyrotropy of surface polaritons in Weyl semimetals

“…A number of recent studies have suggested that Weyl semimetals (WSMs) should have highly unusual optical response originated from unique topological properties of their bulk and surface electron states; see e.g. [1][2][3][4][5][6][7][8][9][10][11][12][13] and references therein. Their optical response can be used to provide detailed spectroscopic information about their electronic structure which could be difficult to obtain by any other means.…”

A new route to negative refractive index from topological metals

“…Note added: After completion of this work, we found a similar work discussing the negative refraction in Weyl semimetals based on anomalous Hall effect [23]. Our proposal might be robust compared to Ref.…”

“…Our proposal might be robust compared to Ref. [23], since it does not rely on microscopic structures of Weyl nodes, and can be applied to both of Weyl and Dirac semimetals.…”

Weak-value amplification for Weyl-point separation in momentum space

“…Recently, ideal Weyl nodes was achieved in artificial photonic crystal structures [10]. WSM has attracted much attention due to its many exotic properties induced by the Weyl nodes, such as anomalous Hall effect [1,11], surface states with Fermi arcs [12,13], peculiar electromagnetic response [14,15], and negatice magneto-resistivity [16][17][18][19]. A WSM can be proved by observing its Fermi arcs with separated Weyl nodes.…”