Towards quantum cellular automata operation in silicon: transport properties of silicon multiple dot structures

The transport properties of two adjacent double dots, realized in silicon is studied by DC-measurements at a temperature of 4.2 K. From the measured charging diagrams the capacitances within the structure are estimated and using this information as input for a simple electrostatic model the energy scales for electron transitions between two dots are calculated. The change of energy in one pair introduced by an interdot electron transition in the other, the basic transition for the operation of quantum cellular automata, is shown to be less than the thermal energy under the present conditions. Adding an extra electron into the system causes larger energy changes in the double dots and for such transitions a clear correlation in electron transport for both double dots can be observed. The size of this effect complies with our model and the estimated capacitances and can therefore be used as a base for future cell design.