Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

In principle, non-contact atomic force microscopy (NC-AFM) now readily allows for the measurement of forces with sub-nanonewton precision on the atomic scale. In practice, however, the extraction of the often desired ‘short-range’ force from the experimental observable (frequency shift) is often far...

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Main Authors: Sweetman, Adam, Stannard, Andrew
Format: Article
Published: Beilstein-Institut 2014
Subjects:
Online Access:https://eprints.nottingham.ac.uk/31698/
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author Sweetman, Adam
Stannard, Andrew
author_facet Sweetman, Adam
Stannard, Andrew
author_sort Sweetman, Adam
building Nottingham Research Data Repository
collection Online Access
description In principle, non-contact atomic force microscopy (NC-AFM) now readily allows for the measurement of forces with sub-nanonewton precision on the atomic scale. In practice, however, the extraction of the often desired ‘short-range’ force from the experimental observable (frequency shift) is often far from trivial. In most cases there is a significant contribution to the total tip–sample force due to non-site-specific van der Waals and electrostatic forces. Typically, the contribution from these forces must be removed before the results of the experiment can be successfully interpreted, often by comparison to density functional theory calculations. In this paper we compare the ‘on-minus-off’ method for extracting site-specific forces to a commonly used extrapolation method modelling the long-range forces using a simple power law. By examining the behaviour of the fitting method in the case of two radically different interaction potentials we show that significant uncertainties in the final extracted forces may result from use of the extrapolation method.
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spelling nottingham-316982020-05-04T16:43:50Z https://eprints.nottingham.ac.uk/31698/ Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces Sweetman, Adam Stannard, Andrew In principle, non-contact atomic force microscopy (NC-AFM) now readily allows for the measurement of forces with sub-nanonewton precision on the atomic scale. In practice, however, the extraction of the often desired ‘short-range’ force from the experimental observable (frequency shift) is often far from trivial. In most cases there is a significant contribution to the total tip–sample force due to non-site-specific van der Waals and electrostatic forces. Typically, the contribution from these forces must be removed before the results of the experiment can be successfully interpreted, often by comparison to density functional theory calculations. In this paper we compare the ‘on-minus-off’ method for extracting site-specific forces to a commonly used extrapolation method modelling the long-range forces using a simple power law. By examining the behaviour of the fitting method in the case of two radically different interaction potentials we show that significant uncertainties in the final extracted forces may result from use of the extrapolation method. Beilstein-Institut 2014-04-01 Article PeerReviewed Sweetman, Adam and Stannard, Andrew (2014) Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces. Beilstein Journal of Nanotechnology, 5 . pp. 386-393. ISSN 2190-4286 Background subtraction DFM F(z) Force Atomic resolution NC-AFM Si(111) STM van der Waals http://www.beilstein-journals.org/bjnano/single/articleFullText.htm?publicId=2190-4286-5-45 doi:10.3762/bjnano.5.45 doi:10.3762/bjnano.5.45
spellingShingle Background subtraction
DFM
F(z)
Force
Atomic resolution
NC-AFM
Si(111)
STM
van der Waals
Sweetman, Adam
Stannard, Andrew
Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title_full Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title_fullStr Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title_full_unstemmed Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title_short Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
title_sort uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces
topic Background subtraction
DFM
F(z)
Force
Atomic resolution
NC-AFM
Si(111)
STM
van der Waals
url https://eprints.nottingham.ac.uk/31698/
https://eprints.nottingham.ac.uk/31698/
https://eprints.nottingham.ac.uk/31698/