Photon-assisted Fano and Kondo resonance in an Aharonov-Bohm interferometer

We have investigated the photon- assisted tunneling through an ultra- small quantum dot (QD) embedded Aharonov- Bohm (AB) interferometer under the perturbation of external microwave fields (MWFs). The tunneling current is derived by using nonequilibrium Green's function technique. The local density of state at finite Coulomb interaction, the differential conductance resonance, current oscillation with respect to AB flux influenced by the nature of the QD and bridge channel have been studied. The MWFs generate novel resonant and Fano structures, which are sensitively dependent on the irradiation approach of MWFs. Novel Kondo peaks can be seen due to the photon- assisted tunneling, and the asymmetric Fano structure also exhibits itself in the photon- assisted satellite peaks and valleys. Our system can be employed as an interferometer to produce novel output signals by controlling the applied MWFs. Copyright (C) EPLA, 2008.