Nonequilibrium transport in T-shaped double quantum dots: Phonon emission without dephasing

We theoretically study the effect of electron–phonon interaction on transport properties in T-shaped double quantum dots, in which one of the dots is connected to the external leads (dot 1) and the other is disconnected (dot 2). Nonequilibrium transport under finite bias is calculated using Keldysh Green function method. The differential conductance shows a dip due to the destructive interference between an electron wave passing by the interdot bonding orbital and that passing by the interdot antibonding orbital. The phonon emission from dot 2 breaks the interference and reduces the dip in size. The phonon emission from dot 1, on the other hand, does not affect the interference at all. An experiment to observe this dephasing-free phonon emission is proposed.