Single-electron charging and detection in a laterally coupled quantum-dot circuit in the few-electron regime

We provide a physical analysis of the charging and detection of the first few electrons in a laterally coupled GaAs/AlGaAs quantum-dot ~LCQD! circuit with integrated quantum point contact read-out. Our analysis is based on the numerical solution of the Kohn-Sham equation incorporated into a three-dimensional selfconsistent scheme for simulating the quantum device. Electronic states and eigenenergy spectra reflecting the particular LCQD confinement shape are obtained as a function of external gate voltages. We also derive the stability diagram for the first few electrons in the device, and obtain excellent agreement with experimental data.