Quantum interference on electron wave spreading over a coupled dot

The characteristics of the conductance fluctuations, observed in the low-temperature magnetoresistance of an open quantum-dot molecule formed from a pair of split-gate quantum dots, have been studied. The evolution of these fluctuations suggests a decrease in the typical area for coherent interference with decreasing the coupling strength between the two dot. We discuss this behavior in terms of a transition from multi- to single-dot interference as a function of the inter-dot coupling. Moreover, an existence of interference trajectories which were independent of the dot coupling was also found in our analysis.