Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips

We use dynamic scanning capacitance microscopy to image compressible and incompressible strips at the edge of a Hall bar in a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. This method gives access to the complex local conductance, Gts, between a sharp metallic tip scan...

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Main Authors: Suddards, M.E., Baumgartner, A., Henini, M., Mellor, Christopher J.
Format: Article
Published: IOP Publishing 2012
Online Access:https://eprints.nottingham.ac.uk/2340/
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author Suddards, M.E.
Baumgartner, A.
Henini, M.
Mellor, Christopher J.
author_facet Suddards, M.E.
Baumgartner, A.
Henini, M.
Mellor, Christopher J.
author_sort Suddards, M.E.
building Nottingham Research Data Repository
collection Online Access
description We use dynamic scanning capacitance microscopy to image compressible and incompressible strips at the edge of a Hall bar in a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. This method gives access to the complex local conductance, Gts, between a sharp metallic tip scanned across the sample surface and ground, comprising the complex sample conductance. Near integer filling factors we observe a bright stripe along the sample edge in the imaginary part of Gts. The simultaneously recorded real part exhibits a sharp peak at the boundary between the sample interior and the stripe observed in the imaginary part. The features are periodic in the inverse magnetic field and consistent with compressible and incompressible strips forming at the sample edge. For currents larger than the critical current of the QHE break-down the stripes vanish sharply and a homogeneous signal is recovered, similar to zero magnetic field. Our experiments directly illustrate the formation and a variety of properties of the conceptually important QHE edge states at the physical edge of a 2DEG.
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spelling nottingham-23402020-05-04T20:21:28Z https://eprints.nottingham.ac.uk/2340/ Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips Suddards, M.E. Baumgartner, A. Henini, M. Mellor, Christopher J. We use dynamic scanning capacitance microscopy to image compressible and incompressible strips at the edge of a Hall bar in a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. This method gives access to the complex local conductance, Gts, between a sharp metallic tip scanned across the sample surface and ground, comprising the complex sample conductance. Near integer filling factors we observe a bright stripe along the sample edge in the imaginary part of Gts. The simultaneously recorded real part exhibits a sharp peak at the boundary between the sample interior and the stripe observed in the imaginary part. The features are periodic in the inverse magnetic field and consistent with compressible and incompressible strips forming at the sample edge. For currents larger than the critical current of the QHE break-down the stripes vanish sharply and a homogeneous signal is recovered, similar to zero magnetic field. Our experiments directly illustrate the formation and a variety of properties of the conceptually important QHE edge states at the physical edge of a 2DEG. IOP Publishing 2012-08 Article PeerReviewed Suddards, M.E., Baumgartner, A., Henini, M. and Mellor, Christopher J. (2012) Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips. New Journal of Physics, 14 . 08315/1-08315/12. ISSN 1367-2630 http://iopscience.iop.org/1367-2630/14/8/083015 doi:10.1088/1367-2630/14/8/083015 doi:10.1088/1367-2630/14/8/083015
spellingShingle Suddards, M.E.
Baumgartner, A.
Henini, M.
Mellor, Christopher J.
Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title_full Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title_fullStr Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title_full_unstemmed Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title_short Scanning capacitance imaging of compressible and incompressible quantum Hall effect edge strips
title_sort scanning capacitance imaging of compressible and incompressible quantum hall effect edge strips
url https://eprints.nottingham.ac.uk/2340/
https://eprints.nottingham.ac.uk/2340/
https://eprints.nottingham.ac.uk/2340/