Detection of single-charge polarisation in silicon double quantum dots by using serially-connected multiple single-electron transistors

Abstract

Abstract-We investigate novel serially-connected multiple single-electron transistors (MSETs) as a single-charge polarisation readout for silicon integrated charge qubits. We first design and analyse the double single-electron transistors (DSETs) in which double quantum dots are connected in series with two side gates. We show that the DSETs are sufficiently sensitive to distinguish all the single-charge polarization states on the two charge qubits integrated adjacently. We also show the scalability of the MSETs by extending our analysis to a scaled-up system of serial triple single-electron transistors (TSETs) integrated with triple charge qubits. Finally we fabricate the DSETs with double charge qubits on the silicon-on-insulator substrate and observe hysteresis in the Coulomb oscillations of the tunnel current at temperature of 4.2K, which are attributable to the change of polarisation in the double charge qubits.