Far-infrared cyclotron resonance and Faraday effect inBi2Se3

Abstract

The complex Faraday angle and transmission for the topological insulator ${\text{Bi}}_{2}{\text{Se}}_{3}$ were measured in the far infrared in magnetic fields up to 8 T and analyzed in terms of a simple Drude-Lorentz magnetoplasma dielectric model. Bulk carriers dominate the optical response. The bulk carriers are electrons as we determined from the sign of the Faraday angle. We obtain the bulk band-edge cyclotron mass ${m}_{cb}=0.16\ifmmode\pm\else\textpm\fi{}0.01{m}_{e}$ and free-electron concentration in the ${10}^{17}$ range. Electron-phonon interaction effects were found to be weak.