Integrated impedance bridge for absolute capacitance measurements at cryogenic temperatures and finite magnetic fields

Journal article (2019)

Authors

G.J. Verbiest JARA-FIT and 2nd Institute of Physics
H Janssen JARA-FIT and 2nd Institute of Physics
D. Xu Kavli institute of nanoscience Delft, QuTech Advanced Research Centre, QRD/Kouwenhoven Lab - QuTech Advanced Research Centre
X. Ge JARA-FIT and 2nd Institute of Physics
M. Goldsche Forschungszentrum Jülich, JARA-FIT and 2nd Institute of Physics
J von Sonntag JARA-FIT and 2nd Institute of Physics, Forschungszentrum Jülich
T. Khodkov Forschungszentrum Jülich, JARA-FIT and 2nd Institute of Physics
L. Banszerus Banszerus Forschungszentrum Jülich, JARA-FIT and 2nd Institute of Physics
N. von den Driesch Forschungszentrum Jülich
More Authors... External organisation
Research Group
QRD/Kouwenhoven Lab (QuTech Advanced Research Centre) (TU Delft)
Copyright: © 2019 G.J. Verbiest, H. Janssen, D. Xu, X. Ge, M. Goldsche, J. Sonntag, T. Khodkov, L. Banszerus, N. Von Den Driesch, More Authors
DOI: https://doi.org/10.1063/1.5089207
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Published Date

2019

Language

English

Faculty

QuTech Advanced Research Centre

Department

Qubit Research Division

Research Group

QRD/Kouwenhoven Lab

Abstract

We developed an impedance bridge that operates at cryogenic temperatures (down to 60 mK) and in perpendicular magnetic fields up to at least 12 T. This is achieved by mounting a GaAs HEMT amplifier perpendicular to a printed circuit board containing the device under test and thereby parallel to the magnetic field. The measured amplitude and phase of the output signal allows for the separation of the total impedance into an absolute capacitance and a resistance. Through a detailed noise characterization, we find that the best resolution is obtained when operating the HEMT amplifier at the highest gain. We obtained a resolution in the absolute capacitance of 6.4 aF/Hz at 77 K on a comb-drive actuator while maintaining a small excitation amplitude of 15 kBT/e. We show the magnetic field functionality of our impedance bridge by measuring the quantum Hall plateaus of a top-gated hBN/graphene/hBN heterostructure at 60 mK with a probe signal of 12.8 kBT/e.