Electronic transmission through a coupled quantum dot and ring

We investigate the transmission of electrons through a quantum ring coupled to a quantum dot by applying a finite difference approach augmented by exterior complex scaling for the solution of the corresponding time-independent Schrodinger equation. It is shown that the transmission in the presence of an additional ring- or dot-bound electron is energetically suppressed compared with the transmission for a pure quantum dot-ring system, being reminiscent of the so-called Coulomb blockade effect in quantum dots. The different behaviour for varying parameters as well as in the presence of an attractive impurity in the dot is discussed in some detail.