Charge-sensing of a Ge/Si core/shell nanowire double quantum dot using a high-impedance superconducting resonator

Spin qubits in germanium are a promising contender for scalable quantum computers. Reading out of the spin and charge configuration of quantum dots formed in Ge/Si core/shell nanowires is typically performed by measuring the current through the nanowire. Here, we demonstrate a more versatile approac...

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Bibliographic Details
Published in:Materials for quantum technology 2023-09, Vol.3 (3), p.31001
Main Authors: Ungerer, J H, Chevalier Kwon, P, Patlatiuk, T, Ridderbos, J, Kononov, A, Sarmah, D, Bakkers, E P A M, Zumbühl, D, Schönenberger, C
Format: Article
Language:English
Subjects:
charge-sensing
Ge/Si core/shell nanowire
high impedance
holes
NbTiN
quantum dots
resonator
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Summary:Spin qubits in germanium are a promising contender for scalable quantum computers. Reading out of the spin and charge configuration of quantum dots formed in Ge/Si core/shell nanowires is typically performed by measuring the current through the nanowire. Here, we demonstrate a more versatile approach on investigating the charge configuration of these quantum dots. We employ a high-impedance, magnetic-field resilient superconducting resonator based on NbTiN and couple it to a double quantum dot in a Ge/Si nanowire. This allows us to dispersively detect charging effects, even in the regime where the nanowire is fully pinched off and no direct current is present. Furthermore, by increasing the electro-chemical potential far beyond the nanowire pinch-off, we observe indications for depleting the last hole in the quantum dot by using the second quantum dot as a charge sensor. This work opens the door for dispersive readout and future spin-photon coupling in this system.
ISSN:2633-4356
2633-4356
DOI:10.1088/2633-4356/ace2a6