Enhancement of transparency in a double-barrier structure by the Fano antiresonance

We show that the presence of a side-attached state strongly modifies the transmission through a one-dimensional double-barrier system in the window of wave vectors around the Fano antiresonance. Specifically, the interplay between the Fano interference and the size quantization inside the structure gives rise to narrow resonant peaks in the transmission coefficient. The height of the peaks may become close to unity (perfect transmission) even for an asymmetric setup with strong barriers, where the transmission coefficient in the absence of the Fano state is strongly suppressed at all other wave vectors. Thus, the two types of interference phenomena, each by itself leading to the suppression of the transmission, conspire in a peculiar way to produce the transparency enhancement.