Models of the interaction of metal tips with insulating surfaces

• Thomas Trevethan,
• Matthew Watkins and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2012, 3, 329–335, doi:10.3762/bjnano.3.37

• Elastic constant: 148.7 N/m; natural frequency: 189000.0 Hz; setpoint amplitude: 5 nm; Q-factor: 10000.0. Macroscopic van der Waals: Hamaker constant: 0.999 eV; Tip radius: 18.0 nm (a) Side-on view of the structure of the Cr and W cluster tip models. (b) The structure of the periodic Cr tip model. (a

Wavelet cross-correlation and phase analysis of a free cantilever subjected to band excitation

• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2012, 3, 294–300, doi:10.3762/bjnano.3.33

• the liquid environment is principally of interest. In liquids the typical cantilever Q-factor ranges from 5 [18] up to 40, for this reason we will focus our attention on the simulation of low-Q oscillators. Wavelet cross-correlation The wavelet transform has shown great potential in various scientific

• evolution of the oscillator response, when the impulsive driver action has died down. We consider the same excitation as in Figure 3, but with an oscillator that has a much higher Q-factor, Q = 40. The time evolution is shown in Figure 5. We note that the initial displacement is not amplified in proportion

• to the Q-factor, as one would have anticipated on the basis of standard resonance amplification, as can be seen from the comparison with Figure 3. The higher Q-factor manifests as a response of the oscillator that now extends over a longer time span, well beyond the driver pulse. The wavelet cross

Current-induced dynamics in carbon atomic contacts

• Jing-Tao Lü,
• Tue Gunst,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2011, 2, 814–823, doi:10.3762/bjnano.2.90

• window by changing the gate potential. In the following, we look at the bias and gate dependence of the inverse Q-factor (1/Q) and effective phonon number N. The inverse Q-factor for mode i (note we use index i for full modes including the current-induced forces) is defined as where ωi are the

• correlation function, We show the bias and gate potential dependence of the inverse Q-factor and phonon number in Figure 4 and Figure 5. The coupling of these two modes due to the bias (gate) dependent NC and BP force changes their lifetime. The two modes always have opposite dependence. The vibrational

• indicated by an increasing radius with time. The motion is a phase-shifted linear combination of the two modes in (a). We can see the elliptical motion of the carbon atoms from the plot. The enclosed area indicates that work can be done by the current-induced NC force. (a) Inverse Q-factor (1/Q) as a