Time-dependent transport of symmetric Λ-type coupled triple quantum dots: competition between coherent destruction of tunneling and Fano resonance

With the help of the Floquet theory, we study the transport properties of symmetric Λ-type coupled triple quantum dots driven by an ac electric field. Under appropriate conditions, coherent destruction of tunneling (CDT) and photon-assisted Fano resonance (FR) appear because of quantum interference effects. As a consequence of competition between the super-exchange interaction and the CDT there is a drastic competition between the CDT and the FR. The phenomena represent two different ways of coherent electron trapping by which we can control the behavior of electrons and they provide a convenient way to fabricate a quantum switch.