Monday DY 9 : Graphene II ( organised by TT )

We predict and analyze radiation-induced quantum interference effect in low-dimensional graphene based n-p junctions. In the presence of radiation the ballistic transport of electrons is determined by two processes, namely, by the resonant absorption of photons near the "resonant points", and by the strong reflection from the junction interface, occurring at the "reflection points". There are two paths corresponding to the propagation of electrons through the junction, and the interference between these two paths manifests itself by large oscillations of the ballistic photocurrent as a function of the gate voltage or the frequency of the radiation. This coherent quantum phenomenon resembles Ramsey quantum beating and Stueckelberg oscillations well-known in atomic physics. A suitable radiation frequency may be in the THz or in the infrared optical region. The effect can be observed best in oneand two-dimensional n-p junctions based on carbon nanotubes, monolayer or bilayer graphene nanoribbons.