Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

Lim J¹, Ooi K J A^{2, 3}, Zhang C⁴, Ang L K^{1, †}, Ang Yee Sin^{4, ‡}

Real part of the dielectric function ϵ_ii(ω) in each direction for 3D DSMs Cd₃As₂ (a) and Na₃Bi (b). The plasma frequency in each direction ω_p,i corresponds to Re[ϵ_ii(ω)] = 0, indicated by the horizontal dashes in both panels. The plots indicate the vast difference in the dielectric (Re[ϵ_ii(ϵ)] > 1) or metallic (Re[ϵ_ii(ω)] < 0) response of 3D DSMs between directions at a given frequency ℏω/ℰF . Unless otherwise stated, we consider the same parameters as those Fig. 1}