Decoupling and antiresonance in electronic transport through a quantum dot chain embodied in an Aharonov–Bohm interferometer

Electronic transport through a quantum dot chain embodied in an Aharonov–Bohm interferometer is theoretically investigated. In such a system, we find that when the quantum dot chain is symmetrically placed some of its molecular states decouple from the leads. Namely, in the absence of magnetic flux all odd molecular states decouple from the leads, but all even molecular states decouple from the leads when an appropriate magnetic flux is introduced. Interestingly, the antiresonance position in the electron transport spectrum is independent of the change of the decoupled molecular states. When incorporating the many-body effect by only considering the Hubbard term and truncating the motion equation of the Green functions to the second-order, we show that the emergence of decoupling gives rise to the apparent destruction of electron-hole symmetry. By adjusting the magnetic flux through either subring, some molecular states decouple from one lead but still couple to the other, and then some new antiresonances occur.