Electrostatic Cross-Talk Between Quantum Dot and Quantum Point Contact Charge Read-Out in Few-Electron Quantum Dot Circuits

Abstract

This chapter investigates the electrostatic interaction between the quantum point contact (QPC) and the quantum dot (QD). This chapter introduces the laterally coupled quantum dots circuit structure and describes our model for simulating the circuit. Charging paths into the two dots are shown by the curved arrows and the QPC currents are shown by the straight arrows. Our numerical simulations show the cross-capacitive effects between single-electron charging in a QD and the QPC detector response. Due to the electrostatic coupling between the QD and the QPC, the QPC conductance is shifted away from the high sensitivity half-way conductance point when varying the plunger gate bias for charging the dot. A trade off should be made between optimal charge detector sensitivity and limited electrostatic influence of the detector on the quantum dot in design and operation of the quantum dot circuit.