Partial swapping of Fano resonance and bound states in continuum in a correlated double-quantum-dot system

We study the partial swapping of the Fano resonance in a correlated double-quantum-dot (DQD) system connected to normal leads by employing the Keldysh non-equilibrium Green function technique in a Coulomb blockade regime. Two types of asymmetries have been considered which occurs when the DQD system undergoes transition from symmetric parallel to i) series and ii) T-shape geometries. It is found that both types of asymmetries exhibit swapping on varying the interdot Coulomb interaction (U-12), however, mostly in the first one or first two pairs (out of four pairs) of Fano and Breit-Wigner peaks. Further, for particular values of U-12 and dot-lead couplings, one, two or three Fano peaks collapse forming bound states in the continuum (BIC). This partial (non-magnetic) swapping and the formation of BIC is found to result from an interplay of correlation effects and asymmetries in dot-lead couplings. Copyright (C) EPLA, 2011