We investigate by numerical simulation the effect of electrostatic coupling between a quantum point contact (QPC) detector of various geometries and a planar double quantum dot in a few-electron quantum dot circuit. Our simulation is based on solving coupled Kohn-Sham and Poisson equations self-consistently by the finite element method. We use the Slater formula to determine the first electron charging bias point of the plunger gate, and give the corresponding variation of the QPC conductance as a function of the QPC gate bias at that particular point, which we interpret as the detector sensitivity. For all QPC designs, we show that the charging bias point of the plunger gate decreases with increasing QPC gate bias. This effect is enhanced for designs wherein large QPC detection sensitivity is found.
ASJC Scopus subject areas
- Physics and Astronomy(all)