How localized are energy dissipation processes in nanoscale interactions?

Santos, Sérgio; Barcons, Victor; Verdaguer, Albert; Font, Josep; Thomson, Neil H.; Chiesa, Matteo

doi:10.1088/0957-4484/22/34/345401

Cited by 34 publications

(73 citation statements)

References 35 publications

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“…That is, the negative region of slope in A smoothly drives the tip very close to the surface, past the long range forces, to where the more localized repulsive and dissipative forces are found. 18 It can also be readily observed in Fig. 1(a) that, after the negative region in slope in A, d min slightly and also smoothly increases by fractions of nm with decreasing A.…”

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confidence: 57%

“…However, image resolution is generally compromised in NC mode because the tip is on average further from the sample, increasing the effective interaction area as a consequence of the long range van der Waals forces. 3,12,18 In terms of resolution, the advantages of removing the large contact areas related to long range forces have been demonstrated both in ultra-high vacuum, 19 by placing atoms that interact covalently rather than ionically, and in liquid environments, 20,21 since London dispersion forces are negligible in water as compared to air.…”

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confidence: 99%

“…Typically, 11,28 in order to enable the tip to interact via the short-range repulsive forces from which high resolution originates, 18,19,25 large amplitudes (energies) were used to break through the water layer and overcome the prevalent capillary interactions. We report, however, that provided the tip is sharp enough (R < 5 nm), the tip can reach the surface at once and smoothly, i.e., avoiding bi-stability, with free amplitudes (A 0 < 5 nm) an order of magnitude smaller than those in standard repulsive mode (A 0 $ 20-50 nm).…”

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confidence: 99%

“…26 The energy dissipated per cycle in SASS ($1 eV) is also an order of magnitude smaller than that of standard ($10-10 2 eV) repulsive imaging. That is, the imaging conditions in SASS are optimal for high resolution imaging of soft matter since conservative and dissipative forces in SASS originate from the more localized repulsive interactions, 18 while peak forces and energy dissipation are minimized.…”

mentioning

confidence: 99%

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Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging

Santos

Barcons

Christenson

et al. 2013

Applied Physics Letters

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A way to operate fundamental mode amplitude modulation atomic force microscopy is introduced which optimizes stability and resolution for a given tip size and shows negligible tip wear over extended time periods (∼24 h). In small amplitude small set-point (SASS) imaging, the cantilever oscillates with sub-nanometer amplitudes in the proximity of the sample, without the requirement of using large drive forces, as the dynamics smoothly lead the tip to the surface through the water layer. SASS is demonstrated on single molecules of double-stranded DNA in ambient conditions where sharp silicon tips (R ∼ 2–5 nm) can resolve the right-handed double helix.

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confidence: 57%

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confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging

Santos

Barcons

Christenson

et al. 2013

Applied Physics Letters

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“…The AM AFM feedback system has been modeled with the use of Matlab and Simulink as described elsewhere 20 .…”

Section: Methodsmentioning

confidence: 99%

Spatial horizons in amplitude and frequency modulation atomic force microscopy

Font

Santos²,

Barcons

et al. 2012

Nanoscale

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Abstract.In dynamic atomic force microscopy (AFM) the cantilever is vibrated and its dynamics are monitored to probe the sample with nanoscale and atomic resolution. Amplitude and frequency modulation (AM and FM) atomic force microscopy have established themselves as the most powerful, robust and reliable techniques in the field.Nevertheless, it is still debatable whether one or the other technique is preferred in a given medium or experiment. Here, we quantitatively establish the limitations in resolution of one and the other technique by introducing the concept of space horizon SH and quantifying it. The SH is the limiting space boundary beyond which collective atomic interactions do not affect the detection parameters of a given feedback system. We show that while an FM feedback can resolve an atom where an AM feedback might fail, relative contrast is in fact equivalent for both feedback systems. That is, if the AM feedback could detect sufficiently small amplitude shifts and there was no noise, single atom imaging would be equivalent in AM and FM.

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Atomic Force Microscopy Imaging of Macromolecular Complexes

2012

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This chapter reviews amplitude modulation (AM) AFM in air and its applications to high-resolution imaging and interpretation of macromolecular complexes. We discuss single DNA molecular imaging and DNA-protein interactions, such as those with topoisomerases and RNA polymerase. We show how relative humidity can have a major influence on resolution and contrast and how it can also affect conformational switching of supercoiled DNA. Four regimes of AFM tip-sample interaction in air are defined and described, and relate to water perturbation and/or intermittent mechanical contact of the tip with either the molecular sample or the surface. Precise control and understanding of the AFM operational parameters is shown to allow the user to switch between these different regimes: an interpretation of the origins of topographical contrast is given for each regime. Perpetual water contact is shown to lead to a high-resolution mode of operation, which we term SASS (small amplitude small set-point) imaging, and which maximizes resolution while greatly decreasing tip and sample wear and any noise due to perturbation of the surface water. Thus, this chapter provides sufficient information to reliably control the AFM in the AM AFM mode of operation in order to image both heterogeneous samples and single macromolecules including complexes, with high resolution and with reproducibility. A brief introduction to AFM, its versatility and applications to biology is also given while providing references to key work and general reviews in the field.

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How localized are energy dissipation processes in nanoscale interactions?

Cited by 34 publications

References 35 publications

Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging

Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging

Spatial horizons in amplitude and frequency modulation atomic force microscopy

Atomic Force Microscopy Imaging of Macromolecular Complexes

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