Simulation and design of a single charge detector

Abstract

We have performed a numerical simulation of a system made of a quantum dot and a nearby quantum point contact defined, by means of depleting metal gates, in a two-dimensional electron gas at a GaAs/AlGaAs heterointerface. As recent experiments have shown, such a system can be used as a non-invasive detector of single charges being added to or removed from a quantum dot. We have computed the occupancy of the dot and the resistance of the quantum wire as a function of the voltage applied to the plunger gate, and have derived design criteria for achieving optimal sensitivity.