Radiation-induced quantum Fano-type resonances in the transport of N-P-N graphene based junctions

We present a theoretical study of quantum resonances in the ballistic transport of graphene based $N$-$P$-$N$ junction subject to an externally applied electromagnetic field (EF). By making use of the Floquet analysis and the quasi-classical approach we analyze the dynamics of electrons in the presence of time and coordinate dependent potential $U(z,t)$. In the absence of EF the resonant tunneling results in a set of sharp resonances in the dependence of dc conductance $\sigma$ on the gate voltage $V_g$. In irradiated $N$-$P$-$N$ junctions we obtain the Fano-type resonances in the dependence of $\sigma(V_g)$. This \emph{coherent quantum-mechanical phenomenon} is due to the interplay of two effects: the resonant tunneling through quasi-bound states and the quantum-interference effect in the region between the "resonant points", where the resonant absorption (emission) of photons occurs, and junction interfaces.