Optical Control of Electronic States in Three-Dimensional Topological Insulators

Abstract

We present a theory to describe the control of surface electron states in three-dimensional gapless semiconductors of mercury telluride (HgTe) type using a circularly polarized electromagnetic field. Such field is shown to induce electronic states localized near the surface due to the mixing of the conduction band and the valence band of the gapless semiconductor. The branches of these optically induced surface states have linear (Dirac) dispersion typical of topological states. Besides surface branches, this field induces a gap between the conduction band and the valence band of the gapless semiconductor. As a result, a circularly polarized field can turn a gapless semiconductor into a topological insulator.