Now showing items 1-17 of 17

  • Anharmonicity in multifrequency atomic force microscopy 

    Santos Hernández, Sergio; Barcons Xixons, Víctor (2014-07)
    External research report
    Open Access
    In multifrequency atomic force microscopy higher eigenmodes are externally excited to enhance resolution and contrast while simultaneously increasing the number of experimental observables with the use of gentle forces. ...
  • Cantilever dynamics in amplitude modulation AFM: continuous and discontinuous transitions 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Font Teixidó, Josep; Thomson, Neil H. (2010-06-21)
    Article
    Open Access
    Transitions between the attractive and the repulsive force regimes for amplitude modulation atomic force microscopy (AFM) can be either discontinuous, with a corresponding jump in amplitude and phase, or continuous and ...
  • Deconstructing the governing dissipative phenomena in the nanoscale 

    Santos Hernández, Sergio; Amadei, Carlo Alberto; Tang, Tzu-Chieh; Barcons Xixons, Víctor; Chiesa, Matteo (2014-01)
    External research report
    Open Access
    An expression describing the controlling parameters involved in short range nanoscale dissipation is proposed and supported by simulations and experimental findings. The expression is deconstructed into the geometrical, ...
  • Energy dissipation in the presence of sub-harmonic excitation in dynamic atomic force microscopy 

    Chiesa, Matteo; Gadelrab, Karim Raafat; Verdaguer, Albert; Segura, Juan José; Barcons Xixons, Víctor; Thomson, Neil H.; Phillips, M.A.; Stefancich, M.; Santos Hernández, Sergio (2012-09)
    Article
    Open Access
    Amplitude modulation atomic force microscopy allows quantifying energy dissipation in the nanoscale with great accuracy with the use of analytical expressions that account for the fundamental frequency and higher harmonics. ...
  • Enhanced sensitivity and contrast with bimodal atomic force microscopy with small and ultra-small amplitudes in ambient conditions 

    Santos Hernández, Sergio (2013-12-02)
    Article
    Open Access
    Here, we introduce bimodal atomic force microscopy operated with sub-nm and ultra-small, i.e., sub-angstrom, first and second mode amplitudes in ambient conditions. We show how the tip can be made to oscillate in the ...
  • How localized are energy dissipation processes in nanoscale interactions? 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Verdaguer, Albert; Font Teixidó, Josep; Thomson, Neil H.; Chiesa, Mateo (2011-07-29)
    Article
    Open Access
    We describe fundamental energy dissipation in dynamic nanoscale processes in terms of the localization of the interactions. In this respect, the areal density of the energy dissipated and the effective area of interaction ...
  • Investigation of nanoscale interactions by means of subharmonic excitation 

    Santos Hernández, Sergio; Phillips, M.A.; Verdaguer, Albert; Font Teixidó, Josep; Chiesa, Matteo; Gadelrab,, K.; Stefancich, M.; Armstrong, P.; Li, G.; Souier, T.; Thomson, Neil H.; Barcons Xixons, Víctor (2012-08-16)
    Article
    Restricted access - publisher's policy
    Multifrequency atomic force microscopy holds promise as a method to provide qualitative and quantitative information about samples with high spatial resolution. Here, we provide experimental evidence of the excitation of ...
  • Phase contrast and operation regimes in multifrequency atomic force microscopy 

    Santos Hernández, Sergio (2014-04-07)
    Article
    Open Access
    In amplitude modulation atomic force microscopy the attractive and the repulsive force regimes induce phase shifts above and below 90°, respectively. In the more recent multifrequency approach, however, multiple operation ...
  • Quantification of dissipation and deformation in ambient atomic force microscopy 

    Santos Hernández, Sergio; Gadelrab,, K.; Barcons Xixons, Víctor; Stefancich, M.; Chiesa, Matteo (2012-07-20)
    Article
    Restricted access - publisher's policy
    A formalism to extract and quantify unknown quantities such as sample deformation, the viscosity of the sample and surface energy hysteresis in amplitude modulation atomic force microscopy is presented. Recovering the ...
  • Single-cycle atomic force microscope force reconstruction: Resolving time-dependent interactions 

    Santos Hernández, Sergio; Gadelrab, Karim Raafat; Font Mateu, Josep; Chiesa, Matteo (2013-08)
    Article
    Open Access
    Here, we enhance the capabilities of the atomic force microscope (AFM) to show that force profiles can be reconstructed without restriction by monitoring the wave profile of the cantilever during a single oscillation ...
  • Spatial horizons in amplitude and frequency modulation atomic force microscopy 

    Font Teixidó, Josep; Santos Hernández, Sergio; Barcons Xixons, Víctor; Thomson, Neil H.; Verdaguer, Albert; Chiesa, Matteo (2012-01-26)
    Article
    Open Access
    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 ...
  • Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: small amplitude small set-point imaging 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Christenson, Hugo K.; Billingsley, Daniel J.; Bonass, William A.; Font Teixidó, Josep; Thomson, Neil H. (2013)
    Article
    Open Access
    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 ...
  • Subharmonic excitation in amplitude modulation atomic force microscopy in the presence of adsorbed water layers 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Verdaguer, Albert; Chiesa, Matteo (American Institute of Physics (AIP), 2011-12-02)
    Article
    Open Access
    In ambient conditions, nanometric water layers form on hydrophilicsurfaces covering them and significantly changing their properties and characteristics. Here we report the excitation of subharmonics in amplitude modulation ...
  • The intrinsic resolution limit in the atomic force microscope: implications for heights of nano-scale features 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Christenson, Hugo K.; Font Teixidó, Josep; Thomson, Neil H. (2011)
    Article
    Open Access
  • The Mendeleev-Meyer force project 

    Santos Hernández, Sergio; Lai, Chia-Yun; Amadei, Carlo Alberto; Gadelrab, Karim Raafat; Tang, Tzu-Chieh; Verdaguer Prats, Albert; Barcons Xixons, Víctor; Font Teixidó, Josep; Colchero, Jaimer; Chiesa, Matteo (2016-10-28)
    Article
    Open Access
    Here we present the Mendeleev–Meyer Force Project which aims at tabulating all materials and substances in a fashion similar to the periodic table. The goal is to group and tabulate substances using nanoscale force footprints ...
  • Unlocking higher harmonics in atomic force microscopy with gentle interactions 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Font Teixidó, Josep; Verdaguer Prats, Albert (2014-03-11)
    Article
    Open Access
    In dynamic atomic force microscopy, nanoscale properties are encoded in the higher harmonics. Nevertheless, when gentle interactions and minimal invasiveness are required, these harmonics are typically undetectable. Here, ...
  • Wearing a single DNA molecule with an AFM tip 

    Santos Hernández, Sergio; Barcons Xixons, Víctor; Font Teixidó, Josep; Thomson, Neil H. (2015-06)
    External research report
    Open Access
    While the fundamental limit on the resolution achieved in an atomic force microscope (AFM) is clearly related to the tip radius, the fact that the tip can creep and/or wear during an experiment is often ignored. This is ...