Ghost Fano resonance in a double quantum dot molecule attached to leads

We study the electronic transport through a double-quantum dot molecule attached to leads and examine the transition from a configuration in series to a symmetrical parallel geometry. We find that a progressive reduction of the tunneling through the antibonding state takes place as a result of the destructive quantum interference between different pathways through the molecule. The Fano resonance narrows down, disappearing entirely when the configuration is totally symmetric, so that only the bonding state participates in the transmission. In this limit, the antibonding state becomes completely localized.