Strong interband Faraday rotation in 3D topological insulator Bi2Se3

Abstract

The Faraday effect is a representative magneto-optical phenomenon, resulting from the transfer of angular momentum between interacting light and matter in which time-reversal symmetry has been broken by an externally applied magnetic field. Here we report on the Faraday rotation induced in the prominent 3D topological insulator Bi 2 Se 3 due to bulk interband excitations. The origin of this non-resonant effect, extraordinarily strong among other non-magnetic materials, is traced back to the specific Dirac-type Hamiltonian for Bi 2 Se 3, which implies that electrons and holes in this material closely resemble relativistic particles with a non-zero rest mass.