Coulomb blockade correlations in a coupled single-electron device system

Abstract

Single-electron devices, such as metal single-electron transistor (SET) and semiconductor quantum dot (QD), are Coulomb blockade (CB) devices with promising applications in both quantum and classical beyond-Si information technologies. As an example, a coupled SET-QD system can provide an experimental platform for addressing, manipulating, and detecting spin and/or charge-based qubits for quantum information processing. We have designed and fabricated a prototype device in this family: a series-coupled double quantum dot (DQD) with side-coupled and/or top-coupled Al single-electron transistors (Al-SET), and implemented the readout of the single electron charging and CB behaviors in a QD using the Al-SET. The readout operation is manifested by the correlated CB oscillations taking place separately in the SET and in the QD; these oscillations originate from that the change of electrons one by one in the QD. We have developed an electrostatics model to study the CB correlations in the capacitively coupled QD/Al-SET device system, which shows qualitative agreement with our experimental observations. Moreover, our design and device fabrication are compatible with modern semiconductor techniques, and can potentially be scaled up into larger integrated systems with quantum and classic bit operation and measurement circuitry.