Journal Article

FZJ-2020-01581

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Integrated impedance bridge for absolute capacitance measurements at cryogenic temperatures and finite magnetic fields

Verbiest, G. J. (Corresponding author)RWTH* ; Janssen, H.RWTH* ; Xu, D.Extern*RWTH* ; Ge, X.RWTH* ; Goldsche, M.FZJ*RWTH* ; Sonntag, J.FZJ* ; Khodkov, T.RWTH*FZJ* ; Banszerus, L.RWTH* ; von den Driesch, N.FZJ* ; Buca, D.FZJ* ; Watanabe, K. ; Taniguchi, T. ; Stampfer, C.FZJ*

2019
American Institute of Physics [S.l.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/24612  doi:10.1063/1.5089207

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.

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Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)
2. Jülich-Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT)
3. JARA-FIT (JARA-FIT)

Research Program(s):

1. 521 - Controlling Electron Charge-Based Phenomena (POF3-521) (POF3-521)

Appears in the scientific report 2020

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; PubMed Central ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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