Interference of conductance and shot noise properties of photon-assisted transport through a T-shaped double quantum dot

Abstract

We have investigated the time-modulated quantum transport properties of a T-shaped double quantum dot. Transport properties of the model device are strongly influenced by the interplay of the quantum interference due to the T-shape arrangement and the inelastic scatterings due to photon-assisted tunneling processes. Electrons can absorb or emit one or multiple photons to reach the new path introduced by the side dot and therefore induce the quantum interference effect with the resonant or photon-assisted resonant path through the central dot. As a result, asymmetric line shapes due to Fano interference appear at the satellite peaks due to the (multi)photon absorption or emission processes. We further investigated the zero dc bias shot noise properties of the T-shaped device. At moderate ac field strength, local minima of the zero dc bias shot noise can be found at the frequency corresponding to multiphoton assisted transport. The phase properties of the elastic transmission amplitude and local density of states are investigated too. It is demonstrated that the abrupt phase drop by $\ensuremath{\pi}$ due to Fano interference can be greatly modified by the coherent photon-assisted transport.