CONDUCTANCE OSCILLATIONS DUE TO A CONTROLLABLE IMPURITY IN A QUANTUM BOX

We present calculations of conductance in a multiply connected nanostructure with a quantum box geometry. Well-defined conductance oscillations appear which are attributed to the quantum interference effect in the presence of a controllable impurity in the quantum box. As the strength of the impurity potential is modulated, conductance oscillations arise from the constructive and destructive interference for the two electronic paths around the centrally located impurity and a third tunneling path through the impurity. We discuss the dependence of these oscillations on the size of the impurity, in terms of circulating or bound states in the quantum box formed by multiple reflections of the phase-coherent electron. The conductance oscillations are predicted to be strong for realistic structural parameters and robust against increasing temperature.