Optical engineering of the 3D quantum Hall effect in Floquet Weyl semimetals

We study the optical modulation of the three-dimensional (3D) quantum Hall effect in Weyl semimetals by using the four-terminal Hall-bar probing geometry. By utilizing the Floquet theorem, we calculate the Hall conductance under the combined effect of the circularly polarized light (CPL) and the perpendicular magnetic field. The Hall conductance plateaus change from negative values to positive values induced by the left-handed CPL. Moreover, the Hall conductance plateaus keep negative values under the action of the right-handed CPL. Accordingly, the chiral dependence of the Hall conductance can be elucidated in terms of the optical modulation of the spatial distribution of the probability density and the Landau levels induced by the CPL. The Hall conductance depends on the thickness of the Weyl semimetals and is robust against the on-site strong disorders. This work will be instructive for realizing an effective optical modulation of the Weyl orbitals in Weyl semimetals.