ABSTRACT
Quantum point contact (QPC) is a constricted one-dimensional conduction channel formed by properly biasing two closely separated metal gates on top of a two-dimensional electron gas at the interface of a semi conductor heterostructure. It is possible to detect sudden changes in the QPC conductance induced by single-electron charging in the quantum dot (QD) down to its depletion of electrons. We show that the QPC can be properly designed to enhance the detector sensitivity to the single-electron charging in a QD near it. In doing so, we compute, for four designs of the QPC gate geometry, the detector sensitivity in terms of the relative change of the QPC conductance when a single electron is placed in the adjacent QD. We use computer modeling to simulate the correlation between the charging of the quantum states in the laterally coupled quantum dots and the corresponding electrostatic variation in the QPC.
