Figure 4 : Quantized THz Faraday rotation of Dirac fermions.

From: Observation of the universal magnetoelectric effect in a 3D topological insulator

Figure 4

Faraday rotation (a) and Faraday ellipticity (b) in a 3D HgTe TI as a function of the external magnetic field for different gate voltages (colour-coded). The horizontal solid line in a indicates the universal Faraday rotation angle . (c) Gate voltage dependence of the Faraday rotation in a magnetic field of 5 T. The dashed lines in a,c provide the calculated value of the Faraday rotation with realistic parameters of the experiment (including the top-gate electode) and assuming the HgTe conductivity exactly equal to σxy=e2/h. The short-dashed line in c indicates the level. The error bars are estimated taking into account the accuracy of the original transmission data and the uncertainties due to subtraction of weak residual contribution (Supplementary Fig. 1).