Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Sensitive Radio-Frequency Measurements of a Quantum Dot by Tuning to Perfect Impedance Matching
AU - Ares, N
AU - Schupp, F J
AU - Mavalankar, A
AU - Rogers, G
AU - Griffiths, J P
AU - Jones, G A C
AU - Farrer, I
AU - Ritchie, D. A.
AU - Smith, C G
AU - Cottet, A
AU - Briggs, G A D
AU - Laird, E A
PY - 2016/3/24
Y1 - 2016/3/24
N2 - Electrical readout of spin qubits requires fast and sensitive measurements, which are hindered by poor impedance matching to the device. We demonstrate perfect impedance matching in a radio-frequency readout circuit, using voltage-tunable varactors to cancel out parasitic capacitances. An optimized capacitance sensitivity of 1.6 aF/√Hz is achieved at a maximum source-drain bias of 170−μV root-mean-square and with a bandwidth of 18 MHz. Coulomb blockade in a quantum-dot is measured in both conductance and capacitance, and the two contributions are found to be proportional as expected from a quasistatic tunneling model. We benchmark our results against the requirements for single-shot qubit readout using quantum capacitance, a goal that has so far been elusive.
AB - Electrical readout of spin qubits requires fast and sensitive measurements, which are hindered by poor impedance matching to the device. We demonstrate perfect impedance matching in a radio-frequency readout circuit, using voltage-tunable varactors to cancel out parasitic capacitances. An optimized capacitance sensitivity of 1.6 aF/√Hz is achieved at a maximum source-drain bias of 170−μV root-mean-square and with a bandwidth of 18 MHz. Coulomb blockade in a quantum-dot is measured in both conductance and capacitance, and the two contributions are found to be proportional as expected from a quasistatic tunneling model. We benchmark our results against the requirements for single-shot qubit readout using quantum capacitance, a goal that has so far been elusive.
U2 - 10.1103/PhysRevApplied.5.034011
DO - 10.1103/PhysRevApplied.5.034011
M3 - Journal article
VL - 5
JO - Physical Review Applied
JF - Physical Review Applied
SN - 2331-7019
M1 - 034011
ER -