Optoelectronics of topological surfaces

In the bulk, a three-dimensional topological insulator behaves like an ordinary band-insulator. At the surface, however, the topological quantum phase difference leads to conducting states, which have a helical Dirac dispersion. Available topological insulators such as Sb₂Te₃, Bi₂Se₃, and Bi₂Te₃ are low-bandgap semiconductors, which suffer from unintended bulk doping. One major challenge in this field is to obtain and characterize pure surface conductivity at room temperature. In this article, we discuss the possibility to use optoelectronic techniques to characterize, control, and read-out the surface states of three-dimensional topological insulators.