Magneto-optical spectra of topological insulators Bi$_2$Te$_3$, Sb$_2$Te$_3$ and Bi$_2$Se$_3$ in magnetic fields up to 18 Tesla

Topological insulators are a novel class of materials that behave as insulators in the bulk, but have conducting states on the surface. Studies of their behavior in magnetic field is an important avenue towards understanding their complex properties. We will report the results of our magneto-optical measurements of topological insulators Bi$_2$Te$_3$, Sb$_2$Te$_3$ and Bi$_2$Se$_3$ in magnetic fields up to 18 Tesla. In all three compounds we detect magnetic-field induced changes in optical properties, which are most pronounced around the plasma edge. The induced changes are much bigger in Bi$_2$Se$_3$ than in Bi$_2$Te$_3$ and Sb$_2$Te$_3$.