CONDUCTANCE OSCILLATIONS DUE TO A CONTROLLABLE IMPURITY IN A QUANTUM BOX

We present calculations of conductance in a multiply connected nanostr ucture with a quantum box geometry. Well-defined conductance oscillati ons appear which are attributed to the quantum interference effect in the presence of a controllable impurity in the quantum box. As the str ength 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 tun neling path through the impurity. We discuss the dependence of these o scillations on the size of the impurity, in terms of circulating or bo und states in the quantum box formed by multiple reflections of the ph ase-coherent electron. The conductance oscillations are predicted to b e strong for realistic structural parameters and robust against increa sing temperature.