Resonant of non-resonant conductivity of a commensurate topological insulator-graphene heterostructure in terahertz regime
The terahertz optical response of a commensurate topologically insulator(TI)-graphene heterostructure is investigated. The interplay of interlayer hopping and topological band structure leads to additional selection rules for the inter band optical transition. The optical conductivity of such a system exhibits interesting features that do not occur in the two constituent surfaces separately. The transitions between TI bands give rise to resonant peaks in conductivity and transitions between the TI bands and the graphene bands give rise to a non-resonant conductivity.